USER`S MANUAL
Contents
1. digitization compression multiplexing and transmission at one end then reception demultiplexing expansion conversion back to analog and application to the two wire telephone interface at the other end Signaling on hook off hook dialing ringing is handled separately from the voice signals in the 38687 Signaling information is transmitted from one 38687 to its companion unit at the far end by means of a derived signaling channel which shares bandwidth with the framing synchronizing signal of the 38687 and contained within the 56 or 64 Kbps multiplexed aggregate signal The signaling information transmitted varies depending on the operating mode selected for the voice channel The four operating modes are described below FXS In this mode the 38687 provides DC voltage and current talk battery for a local telephone instrument By monitoring the presence or absence of current to the telephone instrument the 38687 detects whether the phone or telephone equivalent is idle on hook or busy off hook This information is then transmitted to the far end 38687 which must be placed in FXO mode The on hook or off hook information is then relayed to the telephone switching equipment by the far end FXO unit Pulse dialing information is handled in the same way as on hook off hook since pulse dialing consists of rapid changes in on hook off hook states Tone dialing consists of audio frequency tones and is therefore transmitted in2. on the rear panel of the unit The DTE can be one of many devices such as computer mainframes mini computers workstations CAD CAM equipment multiplexers LAN bridges video display terminals video conferencing equipment high speed printers etc Typical applications include connection of terminals at a remote location to a mainframe at a central location or connections of a remote PC to a LAN See 4 accompanying diagrams The 38687 is a time division unit whose operation is independent of traffic density or data usage The 38687 provides a data connectivity pipeline for the data channel extended over the 56 Kbps or 64 Kbps facility The 38687 connects to voice telephone equipment through either an RJ 11C type six pin modular jack or an RJ 45X type eight pin modular jack located on the rear panel of the unit The single voice circuit of the 38687 can provide end to end connectivity a single standard telephone circuit with loop signaling ringing and dialing control or a PBX to PBX tie trunk with E amp M signaling control Typical applications are for remote connection of a telephone to a PBX station circuit off premise station or remote connection to an outside telephone line off premise extension The 38687 can also be used to support FAX or analog data transmission between two facilities or can support a point to point voice ringdown circuit hot line When used to connect a phone at a remote location to the PBX at the ce
3. clear channel four wire bipolar DDS compatible Transmit Timing Source Looped from network or internal crystal timing source Diagnostics Local Loopback Remote Loopback and Network Loopback responds to network generated DSU and CSU loopback commands Regulatory Meets or exceeds applicable requirements of FCC Part 68 FCC Part 15 for Class A computing devices and UL requirements for AC powered equipment and equipment connected to the telephone network FCC Registration Number 5LYUSA 32793 DE N Physical External Power Supply 90 to 240 VAC 50 60 Hz UL CSA VDE listed source Power Dissipation Less than 4 watts internal idle less than 10 watts when voice circuits busy Environment 0 to 50 degrees C up to 95 RH non condensing Size 2 1 x 10 2 x 9 7 in H x W x D Weight 2 8 Ibs SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE For further information contact Black Box 1000 Park Dr Lawrence PA 15055 PHONE 724 746 5500 24 Notes 25
4. digitized form through the voice paths see discussion above rather than through the signaling circuits When a busy condition is received by a 38687 in FXS mode from the far end this represents an incoming call condition This causes the 38687 FXS circuit to provide a ringing signal 86 Vrms 20 Hz to the telephone set or PBX or KTS trunk circuit This ringing signal will continue in accordance to the information received from the far end unit until the called party answers or the call is abandoned by the calling party See Figure 2 The 38687 can safely ring up to two standard phones simultaneously CAUTION Excessive ringing loads on the voice circuits can cause damage to the units Each voice channel should be connected to the equivalent of two standard ringers or less FXO The FXO mode is the inverse of the FXS mode Indeed to operate properly a 38687 optioned for FXS mode must have a 38687 optioned for FXO mode at the other end and vice versa When in FXO mode the 38687 s signaling circuits are conditioned to detect an incoming ringing signal representing an incoming call and to provide a DC path loop closure to the PBX or central office switch to indicate on hook off hook status When ringing is detected the FXO end will send a busy indication to the FXS unit at the far end thus instructing it to ring its phone When the far end FXS unit detects an off hook condition it sends a busy to the near end FXO which then provides an
5. eccoogaoaosbtis PfuugSiuks E paS SASA S883 EELS CORB sss o S E Z ESE 82 eoaaa5585S 4721 8 Seras ESIL Sara s SEES SSEL ase AAAA S SCC S kk ON 12345678910 1234567 8910 Voice Switch 1 Data Switch 2 Figure 2 The 38687 comes from the factory with its DIP switches as shown in Figure 2 The two DIP switches S1 and S2 need to be properly set for each particular user s application In general the first DIP switch S1 controls the operation of the voice channel and the second DIP switch S2 controls the operation of the data channel and the telephone line connection Both DIP switches need to be set properly for the unit to function correctly see Figure 2 The two DIP switches S1 and S2 are located on the rear panel of the 38687 In general the first DIP switch S1 controls the voice channel operation and levels and the four wire telco interface Switch S1 is to be set as follows S1 1 S1 2 These two switches control the operating mode of the voice channel of the 38687 1 4 1 5 They are coded in such a way as to configure the 38687 for FXO FXS PLAR or E amp M operation as follows S 1 1 1 2 Voice Channel Mode OFF OFF FXS OFF ON FXO ON OFF PLAR ON ON E amp M When ON 1 3 puts the voice channel in the 16 Kbps coding mode This is the mode that uses the least amount of bandwidth for the voice channel and allows for maximum speed of the data channel This voice coding selection will select GO
6. of 9 6 14 4 19 2 28 8 or 38 4 Kbps the user must select the correct speed setting as in the sync data mode and must select ASYNC operation S2 7 When operating at 9 6 14 4 19 2 28 8 or 38 4 Kbps async data is processed through the microprocessor of the 38687 In this mode the data undergoes an asynchronous to synchronous conversion by the use of a UART device on the 38687 which conforms to the specifications of CCITT recommendation V 14 for async to sync conversion The data is then reformatted in a synchronous form for transmission to the far end within the bandwidth assigned to the data by the multiplexing circuitry of the 38687 The microprocessor receives and sends the data to and from a UART which provides the timing conversions necessary for the handling of asynchronous data again in accordance with V 14 CCITT standard To operate properly in this mode the data must be formatted as either EIGHT BIT NO PARITY or SEVEN BIT WITH PARITY The sense of the parity does not matter since the 38687 will treat the parity bit as a data bit There is no restriction on the number of stop bits When operating in this mode the transmit and receive clocks at the data interface are not used Asynchronous data speeds below 9600 bits per second can be handled in any format and any speed by placing the 38687 data channel in the maximum synchronous mode The data will be transmitted and received through the sync data circuits and will provide accep
7. should be connected to no more than two phones per voice channel see FXS section E amp M In this mode the 38687 interfaces to the tie trunk port of a PBX and provides either a Type or a Type II ERM signaling interface This is a logic level type interface where typically the PBX places battery voltage on the M lead to indicate an off hook condition to the 38687 and the 38687 in return places a ground on the E lead to indicate a busy condition to the PBX The E amp M interface of the 38687 is available on the eight wire modular jack marked ERM and provides for either two wire or four wire voice operation user selectable 9 DATA OPERATION The 38687 is designed to provide one data channel port in addition to the single voice port The port may be used to provide end to end connectivity for synchronous or asynchronous data The 38687 data channel may be user configured for speeds of 9 6 14 4 19 2 28 8 or 38 4 Kbps in synchronous or asynchronous mode In addition lower speeds can be accommodated for asynchronous data by utilizing the digital over sampling mode of operation and addition speeds can be configured for synchronous operation to maximize the data throughput once a particular voice coding scheme has been chosen SYNC DATA When configured for sync data the 38687 data port acts as an end to end pipeline for the data independent of format or protocol In synchronous data mode data is exchanged with the DTE in
8. to all standard network generated loopback patterns and signals at both 56 and 64 Kbps line rates so that the telephone company can initiate diagnostic tests and assist in the resolution of problems with the circuits when necessary All tests are simple to operate and easy to interpret USE OF VLSI TECHNOLOGY The 38687 utilizes Very Large Scale Integration VLSI technology in the form of state of the art microprocessors and Field Programmable Gate Arrays FPGAs to insure high reliability maximum performance low power consumption and compact size This maximizes reliability and minimizes the need for spares FRONT PANEL LED S CONTROL The front panel holds 10 LED S and one LOOPBACK switch for quick identification of all status conditions and convenient selection of test modes COMPACT SIZE The unit is physically compact light and is contained in a housing made of durable plastic designed to sit on a desktop or in an equipment room The 38687 will operate in a broad range of environmental conditions and requires minimal space and no special power or cooling Power for the 38687 is derived from a standard AC wall outlet EASY INSTALLATION The 38687 is designed for easy installation and operation No trained personnel are needed to install or activate the unit All connections are of a plug in connectorized type and are made on the rear of the unit The unit is optioned via two DIP switches located on the rear panel No
9. 2 28 8 Kbps 9 6 14 4 19 2 28 8 38 4 Kbps 32 Kbps Best 9 6 14 4 19 2 Kbps 9 6 14 4 19 2 28 8 Kbps When an invalid combination of DIP switch settings is chosen the LOOPBACK SYNC XMT BUSY and RCV BUSY front panel LEDs will FLASH continuously 12 7 FRONT PANEL INDICATORS AND CONTROLS 38687 XMT RCV VOICE DATA CSU POWER LOOPBACK SIG SYNC BUSY BUSY TD RxD RTS CTS Figure 4 The following describes the ten green LED indicators located on the front of the unit and the operation of the front panel rocker switch of the 38687 Front Panel LEDs as seen left to right POWER LOOPBACK SIG SYNC XMT BUSY RCV BUSY When lit this LED indicates that power is applied to the 38687 unit Located next to the LOOPBACK switch this LED indicates that the 38687 is in a loopback mode When lit indicates a valid signal is being received by the 38687 at its receive pair of the RJ 48S telephone line connection When lit indicates the 38687 receiver framing circuitry is receiving a valid synchronizing signal from its companion 38687 unit at the far end and is properly aligned to the incoming multiplexed signal When lit this LED indicates that a busy off hook condition is being detected at the local telephone voice interface When this occurs the 38687 sends an off hook indication to the far end unit so that the proper signaling state can then be provided to the voice equipment at that end of the circuit W
10. 38687 VOICE DATA CSU 38687 XMT RCV VOICE DATA CSU POWER LOOPBACK SIG SYNC BUSY BUSY TxD RxD RIS CIS USER S MANUAL TECHNICAL PUBLICATION A98 110000 REVISION C October 2001 WARNING This eguipment generates uses and can radiate radio freguency energy and if not installed and used in accordance with the instruction manual may cause interference to radio communications It has been tested and found to comply with the limits for a Class A computing device pursuant to Subpart J of Part 15 of FCC Rules which are designed to provide reasonable protection against such interference when operated in a commercial environment Operation of this equipment in a residential area may cause interference in which case the user at his own expense will be required to take whatever measures may be necessary to correct the interference including possible disconnection of the equipment All rights reserved Printed in USA TABLE OF CONTENTS 1 GENERAL 1 2 FEATURES AND BENEFITS 1 3 APPLICATIONS 4 4 INSPECTION AND INITIAL SELF TEST 5 5 INSTALLATION 6 6 DIP SWITCH SETTINGS 8 7 FRONT PANEL INDICATORS AND CONTROL 13 8 VOICE OPERATION 14 9 DATA OPERATION 16 10 TEST MODES AND MAINTENANCE 19 11 WARRANTY 21 12 REPAIR AND RETURN PROCEDURES 21 13 SPECIFICATIONS 22 1 GENERAL The 38687 is a Voice and Data CSU designed to operate over dedicated leased 56 Kbps or 64 Kbps digital telephone lines The 38687 provides two user inte
11. 7 reguires no special tools adjustments or measurements Installation of the 38687 consists of properly setting the two ten position DIP switches S1 and S2 located on the rear panel of the unit and connecting the voice and data eguipment to the connectors on the unit s rear panel Connection to the telephone network is accomplished by connecting the unit to the modular jack supplied by the telephone company using the modular cord supplied with the unit The Adaptive Distance Egualization circuitry of the 38687 compensates for distance and line guality automatically eliminating the need for adjustments Installation of the voice and data eguipment is accomplished by first setting the two DIP switches to their appropriate settings per Section 6 below and then connecting the data eguipment to the 38687 by connecting an appropriate data type cable with a 25 pin DB 25 connector to the DB 25 type connector marked DATA located on the rear ofthe unit The voice eguipment is connected by using a standard six or eight wire modular cord to connect from the jacks marked LOOP or E amp M on the rear of the unit to the appropriate jacks of the telephone set PBX or outside line to which the 38687 is to be connected The wiring plan of the modular jacks and of the DB 25 connectors follows the standard conventions The telephone line jack is of the RJ 48S type and is wired as follows Transmit pair Pins 1 amp 2 Receive pair Pins 7 8 8 The DB 25 connector f
12. ESENTATIVES 12 REPAIR AND RETURN PROCEDURES If a unit is in need of repair call BLACK BOX for a Return Material Authorization RMA number and return the defective unit freight prepaid along with a brief description of the problem to Black Box 1000 Park Dr Lawrence PA 15055 As specified in our warranty Black Box will repair and return the unit at no charge to the customer providing that the warranty period has not expired and that the unit has not been damaged through misuse If a critical out of service situation exists a replacement unit can be obtained within 24 hours in most cases A purchase order number will be required to insure return of the replacement unit Out of warranty service or replacement is also available Contact Black Box or its authorized representative for more information 21 13 SPECIFICATIONS Data Interfaces User Interface RS 232C RS 530 RS 422 or V 35 supported through a DB 25 female connector Data Speeds 9 6 14 4 19 2 28 8 or 38 4 Kbps for synchronous or asynchronous data user selectable Asynchronous speeds below 9 6 Kbps can be accommodated by operating in maximum synchronous mode Additionally synchronous data can be supported in the MAXimum Bandwidth Control mode allowing for nearly all of the 56 or 64 Kbps output data rate for the data when the voice channel is not in use Supported Leads Transmit Data Receive Data Transmit Clock sync External Transmit Clock sy
13. OD voice quality When OFF 16 Kbps voice coding GOOD is NOT selected When ON the voice channel is configured to operate in the 24 Kbps coding mode This choice of voice operation provides BETTER voice quality while leaving less bandwidth available for data speed Choose this setting if you require improved voice quality but still wish to maintain a high data speed for your data channel When OFF the 24 Kbps voice coding BETTER mode is NOT selected When ON the voice channel is configured to operate in the 32 Kbps coding mode This choice provides the BEST voice quality for the voice channel This setting will provide toll quality voice and will allow for high speed analog data and fax traffic over the voice channel However this setting provides the least amount of bandwidth available to the data channel and limits the speed of the data circuit accordingly When OFF the 32 Kbps voice coding BEST mode is NOT selected 1 6 8 S1 7 These two switches configure the receive voice level of the voice channel when 1 10 the voice channel is operating in any two wire mode This includes FXO FXS PLAR and 2W E amp M operation When the 38687 is configured for 4W E amp M operation these two switches are inactive The two switches are coded to provide output receive levels of 0 dBm 3 dBm 6 dBm or 9 dBm as follows 1 6 S1 7 Receive Output Level 2W OFF OFF 0 dBm OFF ON 3 dBm ON OFF 6 dBm ON ON 9 dBm When ON t
14. OPBACK The LOCAL LOOPBACK is used to test the unit at the location where the test is being performed near end To perform the LOCAL LOOPBACK test place the LOOPBACK switch on the front of the unit in the LOC position The LED next to the switch should illuminate This indicates that the 56 or 64 Kbps output of the 38687 is looped back to its receiver input During this test condition an all ones pattern is transmitted to the network When in LOCAL LOOPBACK observe the states of the SIG and SYNC LEDs If these LEDs are both lit proper operation of the local 38687 is indicated While in local loopback mode the data channel can be tested with a BERT test set if desired The data transmitted on the two data port will be received back on the same port Testing of the voice channels in LOCAL LOOPBACK is not possible since the channels are looped back upon themselves After completion of the LOCAL LOOPBACK test place the LOOPBACK switch back its normal center position The LED next to the switch should turn off Should the LOOPBACK switch remain in the LOC position the LOCAL LOOPBACK condition will be automatically terminated after two minutes and the LED will turn off indicating the test has ended To reestablish the loopback put the switch in the normal position and then back to LOC See Figure 5 19 Voice Channel i Voice gt gt Channel MUX CSU ae CSU s MUX Channel 0 Data p Channel 38687 38687 Originating End Respon
15. TION FOR DATA The 38687 can be user configured for MAXimum bandwidth utilization so as to utilize as much of the 56 Kbps or 64 Kbps digital line for data as possible when the voice channel is not in use This user selection option provides nearly the entire digital bandwidth for the data whenever the voice channel is in the idle or on hook condition STANDARD INTERFACE CONNECTORS The unit contains an RJ 48S type modular telco connector for the line interface and a standard DB 25 connector for the data interfaces on the customer side The voice interfaces are of two types two wire loop signaling or two wire four wire E amp M The two wire loop signaling user port is terminated through a standard RJ 11C type modular jack while the two wire four wire E amp M voice channel is terminated through an eight wire RJ 45X type modular jack Only one of the two voice channel connections is active at any one time All the customer connections to the 38687 are made through easily accessible connectors on the rear panel of the unit FLEXIBLE RANGE OF VOICE INTERFACES The 38687 provides several varieties of interfaces for its single voice circuit The unit may be provisioned to provide a standard telephone interface for dial up access Foreign Exchange Subscriber FXS mode direct connection to a PBX line port or outside telco provided line Foreign Exchange Office FXO mode automatic ringdown from telephone to telephone Private Line Automati
16. accordance with clocks normally provided by the 38687 and derived synchronously from the 56 or 64 Kbps aggregate line output Specifically RS 232C or RS 530 RS 422 data is received by the 38687 on the appropriate transmit data pin of the DB 25 connector and is sent to an elastic storage buffer of 32 bits size This data is loaded into the elastic store buffer either in accordance with the Transmit Clock TC provided from the 38687 to the DTE or in accordance with External Transmit Clock ETC provided by the DTE to the 38687 This selection is made with a DIP switch option as discussed previously When ETC is chosen for the transmit data it should be noted that the DTE clock must be synchronous with the clock provided by the 38687 as Receive Clock RC to avoid clock slips No clock slips can occur when TC is used as the transmit data timing source After the elastic store buffer data is presented to the multiplexer circuit of the 38687 for transmission over the 56 or 64 Kbps aggregate line output The bandwidth of the aggregate dedicated for the data channel is determined by the line speed either 56 or 64 Kbps and by the user s choice of voice coding voice quality A table of the allowable synchronous data speeds for each combination appeared in the previous section For this reason selection of 38 400 bits per second data speed is available only with 16 Kbps voice coding on a 56 Kbps line or with 16 or 24 Kbps voice coding on a 64 Kbps li
17. alignments or adjustments are required LOW POWER CONSUMPTION The unit has a low power consumption and uses an external wallmount power supply supplied with unit which plugs into a standard 120 V 60 HZ or 220 V 50 Hz grounded outlet Due to the low power consumption of the 38687 the unit has no cooling fans or moving parts further enhancing reliability TWO YEAR STANDARD WARRANTY The 38687 Voice Data CSU has a standard two year or optional five year limited warranty which covers parts and labor under normal operating conditions Should service or repair be necessary contact Black Box 724 746 5500 3 APPLICATIONS 56 64 Kbps Digital Line 38687 38687 38687 Voice Data CSU Voice Data CSU Main Site Remote Site Typical Installation Figure 1 The 38687 Voice Data CSU provides end to end connectivity for one voice circuit and one data circuit over a standard 56 Kbps or 64 Kbps digital telephone line such as provided by local telephone companies Basic Digital Services and long distance carriers Digital Data Service Accunet Spectrum of Digital Services etc In these applications the 38687 operates in looped timing mode deriving its timing from the network for purposes of synchronization Connection to the network is via a standard RJ 48S type modular jack The 38687 connects to DTE Data Terminal Equipment via the DB 25 interface connector mounted
18. and whether or not the data speed is optimized when the voice channel is not used The switch operation is as follows S2 3 S2 4 2 5 Data Speed OFF OFF OFF 9 6 Kbps OFF OFF ON 14 4 Kbps OFF ON OFF 19 2 Kbps OFF ON ON 28 8 Kbps ON OFF OFF 38 4 Kbps ON OFF ON 19 2 with MBA Sync only ON ON OFF 28 8 with MBA Sync only ON ON ON 38 4 with MBA Sync only 11 S2 6 S2 7 S2 8 S2 9 S2 10 When ON selects External Transmit Clock to load the input buffer of the data circuit if in synchronous data mode When OFF selects the internal data clock Transmit Clock to load the input data buffer of the data circuit when in synchronous data mode When ON selects ASYNCHRONOUS data operation for the Data Channel When OFF selects SYNCHRONOUS data operation for the Data Channel When ON selects end to end flow control operation for the Data Channel When OFF no end to end flow control is provided for the Data Channel When ON selects 56 Kbps line operation When OFF selects 64 Kbps Clear Channel 72 Kbps line rate line operation When ON Internal Line Timing is selected When OFF Looped Line Timing is selected The following selections of voice and data are allowable combinations Valid Data Speeds Voice Coding 56Kbps Line 64Kbps Line 16 Kbps Good 9 6 14 4 19 2 28 8 38 4 Kbps 9 6 14 4 19 2 28 8 38 4 Kbps 24 Kbps Better 9 6 14 4 19
19. c Ringdown PLAR mode or the unit may be configured to provide an analog voice tie trunk between two Private Branch Automatic Exchanges PABX 2W 4W E amp M interface Each mode is selected by a single switch setting located conveniently on the rear panel of the unit The 38687 is compatible with virtually all telephone sets private automatic branch exchanges PBX and telco provided standard telephone lines FLEXIBLE CHOICE OF DATA INTERFACES The 38687 offers a wide range of choices for the data interface on the customer side The data channel may operate at speeds of 9 6 14 4 19 2 28 8 or 38 4 Kbps either synchronously or asynchronously Additionally lower asynchronous speeds are supported by digital over sampling and higher synchronous rates can be supported when the voice channel is idle to maximize throughput for LAN to LAN traffic The physical interface is through a DB 25 type connector which can be user configured to provide either an RS 232 RS 530 RS 422 or V 35 type of interface electrically Additionally the data channel may be optioned for either sync or async operation and the user may select either DTE or DCE transmit clock when in synchronous mode When in synchronous mode the 38687 is independent of both data protocol and format In all cases the data circuit is independent of traffic type and protocol AUTOMATIC ADAPTIVE EQUALIZATION FOR TELCO SIDE The adaptive equalization circuitry automatically compensates fo
20. ch cause interference with the analog to digital conversion process The resulting voice signal is then sampled at 8000 samples per second and converted to an eight bit digital representation of the samples This method of voice digitization called Pulse Code Modulation conforms with Bell System standards for 14 the transmission of voice information throughout the network The digitized voice signal now represented in 64 Kbps digital form is then presented to the ADPCM digital signal processor for compression of the signal The resulting output is a 16 24 or 32 Kbps compressed voice digital signal which is then sent to the multiplexing circuit of the 38687 for transmission over the aggregate to the companion 38687 at the far end of the telephone line The receive portion of the 38687 voice circuit provides the inverse functions The 16 24 or 32 Kbps compressed digital voice signal is presented to the ADPCM processor by the output of the multiplexer circuit The ADPCM processor then expands de compresses the signal back to a full 64 Kbps voice signal to be acted upon by the digital to analog converter The D to A converter then converts the digital signal back to analog it is passed through a low pass filter to eliminate the effects of the sampling frequency level adjusted and then passed through the line interface circuit to be presented to the two wire telephone pair This completes the end to end process of two wire to four wire conversion
21. ding End Remote Loopback Figure 6 To test the 38687 at the far end place the LOOPBACK switch in the REM position Again the LED next to the switch should light In this mode the near end 38687 will transmit a special loopback code through its 56 or 64 Kbps aggregate signal to the far end unit Upon receipt of the special loopback by the far end unit the far end unit will provide a loopback towards the network and hence towards the testing end This loopback signal from the far end includes a special pattern used to assist in determining proper transmission through the system When both units and the transmission line are operating properly the near end unit will have its SYNC and SIG lights on This condition during the REMOTE LOOPBACK test indicates correct operation of both 38687 units and of the 56 or 64 Kbps telephone connection in between Verification tests can be run by sending BERT tests through the data channels Again this test will terminate automatically after two minutes if the LOOPBACK switch is left in the REM position See Figure 6 If the REMOTE LOOPBACK test described above is not successful the problem is either in the remote 38687 unit or in the transmission line in between The LOCAL LOOBACK test can be performed on the far end unit to determine if that unit is functioning properly If the far end unit passes the LOCAL LOOPBACK test the problem is likely to be in the digital telephone line If a problem is report
22. e transportation company and to the supplier Then perform the following quick and simple self tests 1 Before connecting any of the telco or voice or data cables plug the male connector at the small end of the cord of the external wallmount power supply supplied with the unit into the female receptacle marked POWER on the rear of the 38687 Then plug the wallmount power supply line cord into any standard grounded 110 220 VAC outlet 2 Observe the front panel LED s light emitting diodes The LED marked POWER should be illuminated All other LEDs should not be lit 3 Next place the front panel switch marked LOOPBACK in the position marked LOC left The LED next to the switch and the LED marked SYNC should illuminate This basically indicates normal operation of the unit Place the LOOPBACK switch back to its normal center position 4 Next connect the unit to the telephone line using the modular cord supplied with the unit The unit should be functional when plugged directly into the modular jack supplied from the telephone company If a valid signal is received by the 38687 from the digital telephone line the LED marked SIG will light Having done this the 38687 is ready for connection to the customer side equipment per the next section INSTALLATION 5 INSTALLATION LOOP TONE ps beat Esm RJ11 UNIVERSAL DATA PORT VOICE S1 DATA S2 DO i M ass a A a E FIGURE 3 Installation of the 3868
23. e center position is the NORMAL position When in this position the 38687 operates normally and will transmit and receive voice and data information to and from the far end companion unit When LOOPBACK is placed in the left position LOC the 38687 is put into its local loopback condition In this mode the 38687s transmit 56 or 64 Kbps information is looped back to its receiver and an all ones condition is transmitted to the far end unit This mode is used for troubleshooting and diagnostics per Section 10 below When LOOPBACK is placed in the right REM position the 38687 will send a unique loopback signal to the companion 38687 at the far end causing it to perform a network loopback back towards the local 38687 see Section 10 Note that when the LOOPBACK switch is either in the left LOC or right REM positions the accompanying LED is lit indicating a loopback test condition After 2 minutes if the switch is left in these positions the test is terminated and the LED will go off indicating the test has timed out 8 VOICE OPERATION The 38687 provides one voice channel port derived from the multiplexed 56 or 64 Kbps aggregate line signal The voice channel utilizes Adaptive Differential Pulse Code Modulation ADPCM a method of voice compression approved by the major telephone companies as an acceptable means of reducing voice bandwidth The user has the choice of configuring the voice circuit so as to operate at 16 Kbps 24 Kbps o
24. ed to the telephone company diagnostic tests can be run on the dedicated facility between the two locations The 38687 will respond to the both the standard CSU and DSU loopback signals which are sent by the telephone company s testing equipment These two loopback signals from the telephone network will cause the 38687 to provide a NETWORK LOOPBACK towards the telephone equipment When operating on a 56 Kbps digital line the 38687 supports the CSU Loopback DSU Latching Loopback and DSU Non Latching Loopback When operating on a 64 Kbps digital line the 38687 supports the CSU Loopback and the Latching DSU Loopback only In this condition the telephone company can check the local wiring and transmission from the telephone company central office out to the location of the 38687 equipment This capability aids in the rapid determination of the cause and location of a network transmission problem By utilizing these three types of loopbacks the cause of a problem should be easily identified Should it be determined that a fault exists in one of the 38687 units it should be replaced The units are not field repairable and should be returned to Black Box for repair if necessary If technical assistance is required contact the Black Box Customer Service Department by calling 724 746 5500 20 11 Black Box CORPORATION LIMITED WARRANTY Black Box Incorporated warrants this product against defects in material or workmanship under normal operatin
25. g conditions for a period of 2 two years from the date of purchase This warranty covers the product during the warranty period when in the possession of the original purchaser only In the event service is required the product must be delivered within the warranty period prior authorization required transportation prepaid to Black Box together with evidence of date and place of original owner s purchase You will be responsible for removal and installation of the product In all cases the Black Box warranty is limited to the repair or replacement of defective units LIMITATION OF WARRANTY Black Box will repair or replace at no charge units found to be defective during the two year warranty period Failures attributable to improper use storage or maintenance of the product are not covered by this warranty Black Box s liability is limited to the repair or replacement of defective units This warranty shall not apply to manuals or accessories BLACK BOX INCORPORATED AND ITS REPRESENTATIVES OR ITS AGENTS SHALL IN NO EVENT BE LIABLE FOR ANY GENERAL INDIRECT OR CONSEQUENTIAL DAMAGES ARISING OUT OF OR CAUSED BY THE USE OF OR THE INABILITY TO USE ANY BLACK BOX PRODUCT THIS WARRANTY IS MADE IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED AND OF ALL OTHER LIABILITIES ON THE PART OF BLACK BOX ALL OTHER WARRANTIES INCLUDING THE WARRANTY OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED BY BLAC BOX AND ITS REPR
26. hen lit this LED indicates that the 38687 is receiving a busy off hook condition for the voice circuit from the 38687 unit at the far end of the circuit The 38687 then translates this indication of off hook status into the proper condition of the signaling circuits to the local telephone voice equipment TRANSMIT DATA TxD When lit this LED indicates that the 38687 is receiving a SPACE on its transmit data input pin 2 from the DTE for its Data Channel AND the Data Terminal Ready lead DTR pin 20 for that channel is asserted When not lit this LED indicates that the 38687 is receiving a MARK from the DTE on its transmit data pin OR the DTR lead from the DTE is not asserted 13 RECEIVE DATA RxD When lit this LED indicates the 38687 is sending a SPACE on its receive data output pin 3 to the DTE AND Carrier Detect CD pin 8 is asserted by the 38687 to the DTE When not lit this LED indicates that the 38687 is sending a MARK to the DTE on the receive data lead OR Carrier Detect is low not asserted indicating a loss of valid signal at the receiver of the 38687 RTS When lit this LED indicates that the Request to Send RTS lead of the data interface is asserted by the data terminal equipment CTS When lit this LED indicates that the Clear to Send CTS lead of the data interface is being asserted towards the data terminal equipment by the 38687 The front panel LOOPBACK switch is a rocker type with three positions Th
27. his switch selects 4W E amp M operation of the voice channel When OFF this switch selects 2W E amp M operation of the voice channel Switch S1 8 is only active if E amp M operation is chosen on S1 1 and S1 2 When ON this switch selects 4W voice levels of 16 dBm transmit and 7 dBm receive When OFF this switch selects 4W voice levels of 0 dBm transmit and 3 dBm receive This switch is only active when the voice channel of the 38687 has been configured for 4W E amp M operation When ON this switch selects Type II E amp M signaling When OFF this switch selects Type E amp M signaling This switch is only active when the 38687 voice circuit has been configured for either 2W E amp M or 4W E amp M operation 10 The second DIP switch S2 controls the operation of the data channel and the digital line interface as follows S2 1 8 S2 2 These two switches control the data interface and determine what electrical interface is selected for the data channel The two switches determine whether the data channel interface is electrically RS 232 RS 530 RS 422 or V 35 as follows S2 1 S2 2 Data Channel Interface OFF OFF RS 232 OFF ON RS 530 RS 422 ON OFF V 35 S2 3 S2 4 8 S2 5 These three switches determine the selected data speed and whether or not the MAXimum bandwidth allocation feature is enabled The correct setting of these three switches selects the data channel operating speed to be 9 6 14 4 19 2 28 8 or 38 4 Kbps
28. ht wire modular jack for the E amp M voice telephone connection is an eight wire type with the following wiring Two wire Pair 2W or Transmit Pair 4W Pins 4 amp 5 Receive Pair 4W only Pins 3 8 6 E Lead Pin 2 M Lead Pin 8 SG Lead Pin 7 MB Lead Pin 1 After you make the telco voice and data connections the installation needs only the correct setting of the DIP switches as described in the next section The POWER LED should be on steady and the SIG LED should be lit indicating a successful telephone line connection and presence of the digital signal from the network If a 38687 is already connected to the telephone line at the far end and is configured properly the SYNC LED should be lit indicating the reception of a valid signal from the companion 38687 at the far end of the telephone digital line circuit After connection of the 38687 to the four wire telephone line provided by the local carrier the carrier may request notification of the unit s registration for connection to the public network under the rules of the Federal Communications Commission Part 68 The registration number and other needed information for the 38687 is as follows Registration Number 5LYUSA 32793 DE N Type of Equipment Equipment Providing CSU Functions Including Encoded Analog Content 6 DIP SWITCH SETTINGS DI E E SSF Aa 22D 8 8 EPET ao SSSss 2 SE SSS go Q O O O O lt gs Zo lkxa z 000SS EE ECZGE eesssss n Ss corage
29. nc Receive Clock sync RTS CTS DTR DSR and CD Approximate RTS to CTS Delays 500 microseconds at 38 400 bps 700 microseconds at 28 800 bps 1 millisecond at 19 200 bps 1 4 milliseconds at 14 400 bps 2 milliseconds at 9 600 bps Input Elastic Buffer 32 bits Transmit Data Timing synchronous operation Provided by DCE TC or DTE ETC user selectable Synchronous Data Format Any Asynchronous Data Format 8 Bit no parity or 7 Bit with parity odd or even for speeds of 9 6 Kbps or greater Speeds below 9 6 Kbps may be accommodated in any format by operating the channel in maximum synchronous mode Hardware Flow Control RTS to DCD both directions Voice Interfaces User Interfaces Two wire single pair Tip and Ring supported through RJ 11C six wire type modular jack or two wire four wire E amp M supported through eight wire RJ 45X type modular jack Signaling Types Loop start FXS interface to telephone set loop start FXO interface to station line or telephone line originating from central office switch or PBX or PLAR hot line between two phones or E amp M signaling Types or Il Ringing Signal 86 Vrms 20 Hz two standard phones per channel maximum Longitudinal Balance Greater than 45 dB 200 4000 Hz 22 Input Transmit Level 0 dBm 600 ohms at 1000 Hz produces a 0 dBm0 digital reference signal 2W Output Receive Level 2W A 0 dBm0 received digital reference signal 1000 Hz produce
30. ne The data received from the 16 56 or 64 Kbps aggregate at the far end is fed from the multiplexer circuit to a First In First Out FIFO buffer of 16 bits in the data channel receive circuit The output of the FIFO is then sent to the DTE in accordance with the Receive Clock RC through the data interface on the appropriate pin of the DB 25 connector MAXIMUM BANDWIDTH CONTROL A unique feature of the 38687 Voice Data CSU DSU is the use of MAXimum Bandwidth Control to provide the fastest possible data throughput when the voice channel is not in use Typically used in applications for LAN to LAN connectivity between the two end sites MBC provides essentially all of the 56 or 64 Kbps bandwidth for the data circuit when the voice channel is in an idle on hook state When this feature is enabled by the appropriate setting of DIP switches S2 7 through S2 5 the 38687 will provide the chosen combination of voice coding and data speed when the voice channel is in use then automatically switch to a data only mode allowing maximum data speed when the voice channel is idle When a user originates a call once again on the voice channel the units at each end will then automatically switch back into voice plus data mode The data only mode of the 38687 provides a gapped clock at a 56 or 72 Kbps clocking rate to the DTE and is useable only for SYNCHRONOUS data ASYNC DATA Async data is handled in either of two ways by the 38687 At speeds
31. ntral location the 38687 provides a means for the remote user to have an extension of the PBX equivalent to those on site The use of Adaptive Differential Pulse Code Modulation ADPCM in the 38687 allows the 38687 to provide the unique feature of user selectable voice quality based upon the user s needs for both voice quality and for data speed and throughput The voice circuit can be provisioned to use 16 Kbps good 24 Kbps better or 32 Kbps best voice coding The more bandwidth selected for the voice coding the better the voice quality for the voice channel but less bandwidth remains to be used by the data channel The user has the option of deciding which combination of voice coding and data speeds best fits his application needs The use of ADPCM voice coding provides for a high quality voice connection with minimum transmission delay The 38687 contains all the equipment necessary for all voice and signaling applications including the generators of the ringing and talk battery signals The 38687 can also be used in private point to point network applications see figures providing access over any four wire two twisted pairs facility When used in a private point to point application the unit provides its own clock synchronization via the integral clock generator Internal timing mode 4 INSPECTION AND INITIAL SELF TEST Upon receipt of the equipment visually inspect it for signs of damage Immediately report any damage to th
32. off hook loop closure state to the telephone switching system In this manner the FXS FXO pair together make the two 38687 units at the two ends of the 56 or 64 Kbps line appear transparent to the operation of a normal telephone line Thus the user may establish the same type of telephone services over the circuit derived through the use of the 38687 multiplexers 15 that he or she could by direct connection over a normal telephone pair In other words the 38687 multiplexer will not interfere and will pass essentially unchanged the signaling normally present in a standard telephone line connection see Figure 2 PLAR In this mode the 38687 and its far end companion provide a point to point hot line connection Both units near and far must be optioned as PLAR circuits A telephone instrument is connected at each end Figure 4 When either phone is placed in the off hook condition a busy condition is transmitted to the far end 38687 This will cause the far end phone to ring The ringing will continue at a rate of 2 seconds of ringing 4 seconds of silence until the far end party answers or the near end calling party abandons the call attempt A special feature of the 38687 prevents an inadvertent continuous ringing condition by allowing the far end telephone to ring only twenty times After twenty ringing cycles the 38687 will cease to ring the phone until the near end hangs up then reinitiates the call See Figure 3 The 38687
33. or the data connections follows the convention for DCE eguipment and can be configured by the user to provide the electrical characteristics of an RS 232 RS 530 or V 35 interface When configured as an RS 232 or an RS 530 interface only a standard straight through cable is reguired to connect the 38687 data channel to DTE eguipment When the data channel interface is configured for V 35 or if the user wishes to connect the 38687 to an RS 422 DTE interface an adapter cable is reguired which can be purchased separately from Black Box In particular the 25 pin DB 25 data connector is wired as follows RS 232 RS 530 V 35 Via Adaptor Cable Transmit Data TxD Pin 2 Pins 2 amp 14 Pins P amp S Transmit Clock TC Pin 15 Pins 12 amp 15 Pins Y 8 AA External Transmit Clk ETC Pin 24 Pins 118 24 PinsU amp W Data Terminal Ready DTR Pin 20 Pin 20 Pin H Request to Send RTS Pin 4 Pin 4 amp 19 Pin C Receive Data RxD Pin 3 Pins 3 amp 16 Pins R amp T Receive Clock RC Pin 17 Pins 9 amp 17 Pins V amp X Clear to Send CTS Pin 5 Pin 5 amp 13 Pin D Data Set Ready DSR Pin 6 Pin 6 Pin E Carrier Detect CD Pin 8 Pin 8 amp 10 Pin F Signal Ground SG Pin 7 Pin 7 amp 23 Pin B Protective Ground PG Pin 1 Pin 1 Pin A Ring Indicator RI Pin 22 Pin 22 Pin J The six wire modular jack for the loop voice telephone connections are of the RJ 11C type with the following wiring Two wire Pair Tip amp Ring Pins 3 amp 4 The eig
34. r 32 Kbps When choosing 16 Kbps operation the voice quality derived from the voice circuit is good and fax or analog transmission data transmission may be slow or marginal However in this mode maximum data speed is obtainable When the 38687 is configured for 16 Kbps voice on a 56 Kbps telephone line circuit the user may have up to 38 4 Kbps of data throughput Similarly when the 38687 is configured for 24 Kbps voice the voice quality is noticeably better but less data speed is available Lastly when the 38687 is configured for 32 Kops voice coding best the voice quality is full toll quality and fax and analog data are regularly supported through the voice circuit In this mode data speed is limited to 19 2 Kbps maximum on a 56 Kbps digital line or 28 8 Kbps sync maximum on a 64 Kbps telephone digital line On the transmit input side of the voice circuit the voice signals are received through a balanced line interface circuit which takes the two wire bi directional signal present on the telephone pair and converts the signal into separate transmit and receive audio signals when in two wire operation In four wire E amp M operation the transmit and receive voice signals are already separated on two separate voice pairs to and from the PBX The transmit voice signal is then amplified to produce the correct level and then passed through a bandpass filter The bandpass filter eliminates any high frequency components of the signal whi
35. r distance and line quality of the 56 or 64 Kbps digital line which allows the unit to work error free in normal environments without adjustments Generally the unit need only be plugged into the telco provided modular service jack to begin to transmit and receive information properly INTEGRAL CLOCK GENERATOR The 38687 Voice Data CSU offers two timing modes for synchronization DDS Looped timing from the network derived from the received signal on the 4 wire loop or Internal Int timing via an internal crystal oscillator This offers flexibility by allowing the unit to work in public network applications as well as for use in point to point private applications EXTENSIVE DIAGNOSTIC CAPABILITIES The 38687 offers several test modes for diagnostic purposes It can perform several types of loopbacks designed to isolate and identify faults within the entire network The unit can be placed in a Local Loopback mode which removes it from the external telephone network and causes the data and voice channels to be looped back upon themselves This provides a simple means for testing the 38687 for proper operation The Remote Loopback mode sends a unique signal to the far end 38687 causing it to present a loopback towards the network and back to the near end This enables the user to test the telephone circuit all the way to the far end multiplexer Simple status lamps on the front of the unit indicate proper operation Also the 38687 responds
36. rfaces one voice one data which can be used simultaneously and continually over a single digital leased line These two inputs are derived from a multiplexed signal transmitted and received over a standard 56 Kbps or 64 Kbps digital data telephone line Such 56 or 64 Kbps lines are standard types throughout North America and are provided by local telephone companies or long distance carriers under services known as Dataphone Digital Service DDS Basic Digital Service BDS Accunet Spectrum of Digital Services Sprint Clearline and eguivalents The 38687 Voice Data CSU can be used with telco provided lines or in private networks for high speed point to point applications requiring both voice and data connectivity The 38687 advanced design compact size and reliability make it an ideal product for most applications reguiring the transmission of simultaneous voice and data over a single dedicated digital facility 2 FEATURES AND BENEFITS SIMULTANEOUS VOICE AND DATA OPERATION The unit operates continually over a single standard 56 or 64 Kbps digital telephone line on the network side and provides one sync or async data connection and one voice telephone type connection on the customer user side The two user interfaces one voice one data are independent of each other and may be operated simultaneously over the single digital telephone line No blocking or slowdown of data or throughput will occur AUTOMATIC BANDWIDTH OPTIMUMIZA
37. rol leads to and from the DTE is a standard unbalanced RS 232C compatible signal END TO END HARDWARE FLOW CONTROL The 38687 supports hardware flow control from end to end By placing S2 8 in the ON position RTS to DCD flow control is supported in each direction 18 10 TEST MODES AND MAINTENANCE The 38687 Voice Data CSU provides a wide range of diagnostic capabilities for easing testing troubleshooting and maintenance Testing and diagnostic troubleshooting for the 38687 consists of operation of the various loopback capabilities of the unit and observance of the LED indicators on the front of the unit to verify correct operation Additional more comprehensive testing can be performed with the use of transmission test sets for the voice channels and or BERT type data test sets for the data channels For most situations however the simple diagnostics resident within the 38687 should be adequate Testing for the 38687 is accomplished through the use of the three types of loopbacks available in the unit The three types of loopbacks used in the 38687 are LOCAL REMOTE and NETWORK By utilizing these various loopbacks a user at one end of a telephone line connection can successfully test the near end 38687 unit the far end unit and the telephone circuit in between Voice Channel a All Ones A MUX CSU To DDS Data 4 4 Network Channel d e y 38687 Local Loopback Figure 5 The first diagnostic of use in the 38687 is the LOCAL LO
38. s a 0 3 6 or 9 dBm 1 dB signal at receive port 4W 0 dBm transmit 3 dBm receive or 16 dBm transmit 7 dBm receive Signal to Noise Ratio Greater than 20 dB at 0 dBm0 at 16 Kbps coding greater than 30 dB at 24 or 32 Kbps coding Idle Noise Less than 20 dBrnCO Frequency Response Relative to 1000 Hz level 3 dB 300 3000 Hz Dialing Supports tone DTMF and pulse dialing Over voltage Protection Per FCC Part 68 requirements Telco Interface Line Interface 4 Wire non loaded cable Line Speed 56 Kbps or 64 Kbps Connector RJ 48S Equalization Automatic Adaptive no alignments or adjustments Modulation Bipolar Return to Zero Transmit Output Impedance 135 ohm 10 Receive Input Impedance 135 ohm 10 Transmit Output Level 1 4 V peak Receive Input Sensitivity 46 dBmO Range Approx 3 0 to 9 5 miles depending on wire gauge FCC Approval Meets applicable requirements of FCC Part 68 and FCC Part 15 Subpart J for a Class A computing device FCC Part 68 Registration Number 5LYUSA 32793 DE N Compatibility Meets requirements of AT amp T PUB 62310 for standard DDS service compatibility 23 General Number of Voice Channels Ports 1 Voice Type 16 24 or 32 Kbps ADPCM user selectable derived from u law companded 68 bit PCM 8000 Hz sample rate Number of Data Channels Ports 1 Data Type Synchronous or Asynchronous RS 232C RS 530 RS 422 or V 35 compatible Aggregate 56 or 64 Kbps
39. table performance for any standard low speed asynchronous terminal or other device CONTROL LEADS The 38687 supports several control leads for its data interface in both sync and async mode The 38687 will accept as inputs in addition to data and clock Data Terminal Ready DTR and Request to Send RTS The 38687 will provide as outputs in addition to data and clocks Data Set Ready DSR Clear to Send CTS and Carrier Detect CD The 38687 responds to Request to Send with the assertion positive voltage of Clear to Send after a timed delay of 20 clock cycles The RTS CTS delays are as follows Data Speed RTS CTS Delay 9 6 Kbps 2 milliseconds 14 4 Kbps 1 4 milliseconds 19 2 Kbps 1 milliseconds 28 8 Kbps 700 microseconds 17 38 4 Kbps 500 microseconds DTR received from the DTE has no effect on the 38687 other than the transmit data LEDs on the unit s front panel will illuminate only when DTR is asserted DSR asserted by the 38687 indicates that a valid signal is being received at the 56 or 64 Kbps input port and that the unit is not in a local loopback condition The Carrier Detect CD signal asserted by the 38687 means a valid signal is received by the 38687 at its aggregate line receive port and the unit may possible be in loopback mode The receive data LED on the front panel will light only when CD is asserted DCD can also be placed under control of the far end lead for end to end hardware flow control Each of the cont
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