AM64/128A BASE BAND MODEM USER MANUAL ATL Part No. 1/203/002/610 Issue 4 - September 2002.
AM64/128A User Manual THE INFORMATION CONTAINED IN THIS DOCUMENT IS CONFIDENTIAL TO ATL TELECOM LTD. AND MAY NOT BE DISCLOSED OR REPRODUCED IN WHOLE OR IN PART WITHOUT THEIR WRITTEN CONSENT. ©ATL TELECOM LTD. 2002.
Contents AM64/128A User Manual CONTENTS 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 2. Constructional Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2.1 Base Band Modems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2.2 Interface Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 3.
AM64/128A User Manual 5.6 Contents Option Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 5.6.1 5.6.2 5.6.3 5.6.4 5.6.5 5.6.6 5.7 X.21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 X.21bis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 G.703 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 Asynchronous Mode . . . . . . . . . . . . .
Introduction 1. AM64/128A User Manual INTRODUCTION This manual applies to the AM 64/128A Baseband Modem. This modem is manufactured in the U.K. by ATL Telecom Ltd. There are six variants, each with a different physical data interface circuit. The ATL Telecom Ltd. part numbers for these variants are as follows :• • • • • • AM 64/128A - X.21 : AM64/128A - X.21bis : AM64/128A - V.35 : AM64/128A - V.36 : AM64/128A - RS530 : AM64/128A - G.
Constructional Details 2. CONSTRUCTIONAL DETAILS 2.1 Baseband Modems AM64/128A User Manual The BBM is housed in a black plastic case. On the front panel there is a menu driven LCD display with six keys and five LED's. On the back panel there is a 3- pin IEC mains inlet socket, an input voltage selector switch (230V/120V), a 6-way - 4-loaded RJ11 connector type line cord socket, and one data interface connector.
System Overview 3. AM64/128A User Manual SYSTEM OVERVIEW The AM64/128A baseband modem uses the digital transmission system designed and developed by ATL Telecom Ltd. in Cardiff. It is intended for operation on 2-wire local telephone network circuits, such as those meeting BT EPS-9 (2-Wire). It will operate satisfactorily on unloaded lines having a wide range of characteristics; bridge taps can be tolerated, dependent upon their characteristics.
AM64/128A User Manual System Overview The interface circuit performs a number of functions : it converts between the user data from the appropriate interface and the 64kbps or 128kbps, which is transmitted down the line; it links the control circuit to the control channel; it interfaces the control circuit to the control lines of the data ports. Again, these functions are performed by a custom IC supported by a number of standard components.
Installation 4. AM64/128A User Manual INSTALLATION This chapter describes the basic steps that are required to set up a system involving the Baseband Modems (BBM's). There are two basic systems that will be considered: (1) BBM connected to BBM (2) BBM connected to Line Card When considering the installation general pointers to the configuration of the BBM's are given. It should be noted that there are many BBM parameters which may be set differently and prevent the results from being as expected.
AM64/128A User Manual Installation Set the line rate (section 5.7.2) as required at both ends, and set the user data rate up on the master (section 5.5). When the line is connected the FAULT LED should go out. The interface details and synchronous or asynchronous working should now be configured at both ends. This is done using the option menu (section 5.6). Note : When the AM64/128A has the G.703 interface fitted, then the unit is only operational in Master mode and a user rate of 64kbps.
Installation AM64/128A User Manual 4.2 BBM to Line Card Link Power up the BBM as described previously, and set the modem to slave mode. Set the line rate as required, and connect the line cord. Consult the line card handbook to set up the user data rate. The modem should automatically program to this rate. There will be an ‘options enable’ switch on the line card which determines whether the interface details are to be set either from the line card or modem.
Menu Operation AM64/128A User Manual 5. MENU OPERATION 5.1 Front Panel Features The Baseband Modem has an uncluttered and easy to understand front panel. It has a liquid crystal display (LCD), 5 LED’s, and 6 non-locking keys. With the 16 character alphanumeric, dot-matrix liquid crystal display it is possible to describe most of the functions in plain English, thus avoiding having to use complicated mnemonics and the need to constantly refer to a hand book.
AM64/128A User Manual Front Panel Operation 5.2 Front Panel Operation The LCD will display one of five menus at any one time, these menus are: 1. 2. 3. 4. 5. STATUS TEST RATE OPTION CONFIG (Prompt (Prompt (Prompt (Prompt (Prompt is is is is is S>) T>) R>) O>) C>) In normal circumstances, the front panel LCD will display a Status message relating to the overall state of the data link e.g. READY. Additional status information may be displayed by scrolling down through the menu.
Status Menu 5.3 AM64/128A User Manual Status Menu The status menu is read only, which means the select button has no effect. It provides the following data: (1) (2) (3) (4) (5) (6) Overall status Alarm messages User data rate Line rate Interface status Operating mode 5.3.
AM64/128A User Manual Alarm Status 5.3.2 Alarm Status The possible messages for this item are: S > No Alarm S > No Signal S > Receiving AIS S > No Alignment The S > No Signal display indicates that the transmission system cannot find a signal to lock on to.
Status Menu AM64/128A User Manual 5.3.3 User Rate This item displays the user rate in current use. A complete list is given in section 5.5 - Rate Menu. For example: S > 48K 10 5.3.4 Line Rate This has to be set locally to the BBM via the front panel and cannot be downloaded from the Master unit. This displays the line rate in use: If the high line rate (71.1kbps) is selected then the display is: S > 64K Rate Note : This is the only rate available with G.703 Interface. If double line rate (142.
AM64/128A User Manual Menu Operation - Status Menu 5.3.6 Operating Mode The BBM is capable of operating in two basic modes: S > Link Mode S > Network Mode For a BBM to BBM link this display should read Link Mode. If however a Line Card is used instead of a master BBM, then the display should read Network Mode.
Menu Operation - Test Menu 5.4 AM64/128A User Manual Test Menu 1. 2. 3. 4. 5. 6. 7. 8. 9. Local loop Loop back Remote loop Binary pattern Data error test In service error test Lamp test Self Test Comms channel loop 5.4.1 Local loop This is a loop applied within the local BBM. It loops data back to the DTE from a point as close to the interface connector as possible. This loop can be applied in two ways (1) (2) From the Menu. Direct from the DTE - see section 5.4.1.2. 5.4.1.
AM64/128A User Manual Test Menu With a G.703 Interface fitted, the application of a local loop will cause G.703 data to be looped back to the G.703 network at the G.703 interface (known as a Loop B / LCB loop on the G.703 linecard and standalone units) as shown in figure 5.4.1.2 below. 5.4.1.2 Local loop from DTE To apply a local loop in this fashion refer to your DTE equipment handbook for details on how to send the pattern.
Test Menu AM64/128A User Manual With a G.703 interface fitted, the application of a loopback will apply a loopback to line at the remote slave unit (known as an LTU loop on the G.703 linecard and standalone units). Note : It is not possible to “Hardwire” a G.703 loop at the G.703 interface connector. 5.4.3. Remote Loop Remote loop involves turning on a BBM loopback, but from the other end of the link (see figure 5.4.3). This can only be menu activated from a BBM with a X.21bis interface.
AM64/128A User Manual Test Menu 5.4.3.2 Remote loop from DTE When the BBM receives an ART pattern (00110011) from the DTE (in X.21), or when circuit 140 is active (in X.21bis) the loopback is applied on the remote BBM similarly to the above. To apply a remote loop in this fashion refer to your DTE handbook for details. The BBM can be in any menu when this loop is applied, it does not have to be in the Test Menu.
Test Menu AM64/128A User Manual 5.4.5 Data Test 5.4.5.1 Overview This mode allows the user to send a binary 0's pattern to the remote BBM and monitor the received data stream for errors Note : every binary 1 received is treated as a single error. The number of bits received in error is displayed on the LCD. The test time elapsed can also be displayed, allowing the user to calculate the effective Bit Error Rate if required.
AM64/128A User Manual Test Menu The Data Test can be used to test the performance of a link (0 or 1 patterns on the two wire line are all AMI encoded and framed as described in section 3). Note: Apply any loops required before entering Data Test Mode. Enter the test menu and scroll to : T> Data Test then press SELECT. There are four displays within this Data Test sub-mode: 1. 2. 3. 4.
Test Menu AM64/128A User Manual 2/ Pattern display The pattern display usually shows Injecting 0s Pressing SELECT will cause binary 1s to be injected (e.g. for loop verification): Injecting 1s This pattern will continue to be injected until the SELECT key is pressed again, (or the mode is exited).
AM64/128A User Manual Test Menu 5.4.6 In Service Test 5.4.6.1 Overview This mode allows the error performance of the line to be monitored, without interrupting data traffic. This works by monitoring the accuracy of some of the overhead bits that make up the transmission frame structure. As the data channel itself is not monitored, the figures produced cannot accurately be extrapolated to give the data error rate, but can be used as a general guide.
Test Menu AM64/128A User Manual 5.4.7 Lamp Test This facility is used to check the LED’s and the LCD display. To activate the test choose the item T > Lamp Test Pressing SELECT will cause a complete line of blocks to show on the LCD. Simultaneously all the LED's should light up, for about 3 seconds. On completion, the LCD will return to the display above. 5.4.
AM64/128A User Manual Test Menu However, the usage of the EEPROM (Blocks Used) is still displayed for information. For example: 000 means that the first block is in use and that there are 254 empty blocks. 254 means that the last block is being used and the chip is nearly full. The failure messages have the following implications: 1. EPROM Fail 2. EEPROM Fail This is a fatal error and the program will terminate. This indicates that the internal structuring of the EEPROM data is corrupt.
Menu Operation - Rate Menu 5.5 AM64/128A User Manual Rate Menu The rate menu is only accessible in master mode. In slave mode the user rate is dictated by the master BBM. The rate can then only be viewed in the status menu. This menu consists of a number of data rates from which one can be selected, except for 128k line rate, where 128k data rate is automatically selected. The actual rates available depend on the modem interface type.
AM64/128A User Manual Rate Menu The Rate menu operates slightly different when 64k mode is activated. It is described more fully in the Configuration Menu (Section 5.7). Briefly, this mode involves the master BBM set to 64K + BT, and the slave BBM set to some other rate. As far as the rate menu is concerned there are now two separate rates to display; and these are indicated clearly with the words Master or Slave.
Menu Operation - Option Menu 5.6 AM64/128A User Manual Option Menu This menu displays the type of DTE interface currently fitted in the BBM. The AM64/128A automatically “reads” which interface type is fitted on power up, and programs certain options accordingly. The first two display options are read only. These display the following information: (1) Overall protocol type (2) Interface type X.21, X.21bis or G.703 V.11, V.28, V.35, V.36, RS-530 or G.703 In X.
AM64/128A User Manual (3) O > 107 Normal Menu Operation - Option Menu Press SELECT: O > 107=108/1 This allows control line 107 to follow control line 108/1 independent of other factors. (4) O > 108/1 Normal Press SELECT O > 108/1 Set On This option holds the control line 108/1 ON internally. There are three options for the X.21bis V.35, V.36 and RS-530 interface. (1) and (2) as before and : (3) O > 107 Normal Press SELECT O > 107 Set On This holds control line 107 ON permanently.
Menu Operation - Option Menu AM64/128A User Manual 5.6.6 Character Length Scrolling down further gives the display: O > Char Len: 8 Pressing SELECT changes the length between the four options, 8, 9, 10 and 11 bits. The character length sets the total character length including one start bit, one stop bit and possible parity bit.
AM64/128A User Manual 5.7 Menu Operation - Configuration Menu Configuration Menu This menu contains the items that are used in the initial configuration of the BBM. Once set up they are usually left unchanged for normal BBM operation. All of the configuration parameters are stored in nonvolatile memory and are restored each time the BBM is powered up. The items in this menu are as follows: (1) (2) (3) (4) (5) (6) (7) Master - Slave Line rate X.
Configuration Menu AM64/128A User Manual 5.7.3 X.21 Loop Control This facility is designed for when a pair of BBM’s are used as an extension to another BBM link. The concept is shown below. To DTE slave master Modem A Modem B X2.1 Link Modem C Normal BBM to BBM link Modem D To DTE External link or network Figure 5.7.3 BBM’s A and B form part of a conventional link. However in this example, instead of a DTE being connected to BBM B another link is started.
AM64/128A User Manual Configuration Menu 5.7.4.1 Synchronisation Type (for software version V1.3 and above) With these later versions of software, there are three possible options depending upon which interface is fitted, whether Master or Slave mode is selected, and the rate selected. Option 1 - C > Ext Byte Clk This option is shown when the ‘External Byte timing ON’ is selected.
Configuration Menu AM64/128A User Manual 5.7.5 64k Mode This mode is designed to be used in association with the X.50 framing patterns. When the mode is selected the master BBM is set to 64k and the slave is (usually) set to 48k X.50. This allows the master BBM to become transparent to the X.50 framing structure, allowing it to be processed by the master DTE. C > 64K Mode Off The mode is normally OFF, displayed as: Pressing SELECT gives: C > 64K Mode On 5.7.
AM64/128A User Manual Glossary GLOSSARY OF TERMS AIS Alarm Indication Signal. ALT Automatic Local Test. - Pattern sent to apply a local loop in the DCE. AMI Alternate Mark Inversion. - Code used for line transmission. ART Automatic Remote Test. - Pattern sent to apply a loopback on the remote modem. BBM Baseband Modem. BT Byte Timing. - Synchronisation to every 8 bits. CNR Controlled Not Ready DC Direct Current DCE Data Circuit-terminating Equipment. DSP Digital Signal Processor.
Glossary AM64/128A User Manual V.24 CCITT specification. List of definitions for interchange circuits between DTE and DCE. V.28 CCITT specification. Electrical characteristics for unbalanced double-current interchange circuits. (V.28 Interchange circuits defined in V.24) V.35 CCITT specification. Data transmission at 48kbit/s using 60-108kHz group band circuits. V.36 CCITT specification. Modems for synchronous data transmission using 60-108kHz group band circuits. X.21 CCITT specification.
AM64/128A User Manual Specifications GENERAL SPECIFICATIONS Transmission system uses DSP techniques involving echo cancellation and adaptive decision feedback equalisation. The system is intended for use on 2-wire unconditioned copper wire (BT EPS-9 type circuits). Power output selectable 0dBm or 10dBm. Line code is AMI with embedded synch pattern for timing control. Line rates 71.1kbit/s (high) or 142.2kbit/s (double). Line attenuation range up to 50dB at 10dBm output level and high line rate.
AM64/128A User Manual Appendix A - Interface Connections APPENDIX A - Interface Pin Connections 25 Way D - type X.21 bis (V.24 / V.28*) Connector pin allocation *V.28 defines the electrical characteristics of the circuits of a V.24 interface. Note: Circuit 105 Request to send may have to be set in the Options Menu - see Appendix F (Troubleshooting).
Appendix A - Interface Connections AM64/128A User Manual V.35 (MRAC) Connector Pin allocation Note: Circuit 108/1 is not available on the connector as an interface line but is software clamped in the ON state.
AM64/128A User Manual Appendix A - Interface Connections 25 Way D-type RS-530 Connector pin allocation Pin Unbal TYPE A wire B wire Circuit 1 7, 22, 10, 13 Description SITS 89/43 Earth/Shield Common 103(AB) Common Return Common 2 14 103(BA) Transmitted Data Load 3 16 104(BB) Received Data Generator 4 19 105*(CA) Request to Send Load 5 (5) (13) 106*(CB) Ready for Sending Generator 6 (6) (22) 107*(CC) Data Set Ready Generator 8 (8) (10) 109*(CF) Data Channel Rece
Appendix B – Internal Link Settings APPENDIX B – Internal Link Settings A-4 AM64/128A User Manual
AM64/128A User Manual The function of the links is as follows: J1 Transmission disable This link is always left in position 1-2 J11 Watch dog enable This link is always left in position 1-2 J21 This connects the supply earth to the circuit ground in position 1-3 The circuit ground is floating in position 1-2 WARNING Only authorised personnel can be allowed to open the Line Terminat ing Unit case to change the link settings.
AM64/128A User Manual Appendix B – Internal Link Settings Interface Modules X.21 Interface Module: J1 – Circuit 103 Termination. J2 - Circuit 113 Termination. J1 - X.21 T (Transmit data) Circuit Termination – This link connects a 120 ohm load resistor across the T circuit position 1-3. This helps maintain signal rise times and minimises reflections at rates greater than 9.6 kbps over long lines. At lower rates and over short lines the termination resistor may be omitted, (link set position 1-2). J2 – X.
AM 64/128A User Manual Appendix B – Internal Link Settings Interface Modules: RS530 Interface Module: J1 – Circuit 103 Termination. J2 – Circuit 113 Termination. J1 – V36 and RS530 Circuit 103 (Transmit data) Circuit Termination – This link connects a 120 ohm load resistor across the 103 circuit in position 1-3. This helps maintain signal rise times and minimises reflections at greater than 9.6 kbps over long lines.
Appendix C - In Service Test AM64/128A User Manual APPENDIX C - In Service Test BACKGROUND INFORMATION The information passing between master and slave BBM’s comprises of user data and control data; the latter is used for controlling and supervising the operation of the transmission system. In order that these components can be separated the composite data is transmitted in frames with a fixed framing pattern to identify the frame boundary. Data is transferrred at 71.1 kbps at the high rate and 142.
AM64/128A User Manual Appendix C - In Service Test It must be remembered that this error count is unidirectional only. There can be no looping of the envelope alignment bits. This fact can be used to advantage in determining the location of noise on a link. Consider an example where two BBM’s are connected together. BBM1 indicates a high error rate, and BBM2 indicates a low error rate.
Appendix D - Approvals AM64/128A User Manual APPENDIX D - Approvals LVD - Safety Statements: Power Rating Information 1. Voltage Range: 2. Current Range 3. Frequency Range - AC Source: 230/120Vac. 40mA at 230V and 85mA at 120V. 50/60Hz. Safety Instructions: 1. The apparatus must be installed and maintained by COMPETENT SERVICE PERSONNEL. 2. Disconnect power and line connector on the modem before attempting to change the PIM module. 3.
Appendix E - Private digital circuits AM64/128A User Manual APPENDIX E Use on X.21/X.21bis digital circuits - External Timing Configuration The details in this appendix relate to the arrangement shown in figure E.1. The main difference between this arrangement and the conventional link is the need for a special interface cable which joins the master BBM to the private digital circuit.
AM64/128A User Manual Appendix E - Private digital circuits 2. X.21 byte timing cable - (15 way to 15 way D type plugs). CCITT circuit Timing Source (DCE) Timing Sink (DTE) CCITT circuit T-A 2 4 R-A T-B 9 11 R-B R-A 4 2 T-A R-B 11 9 T-B B-A 14 1 SEXT-A B-B 7 15 SEXT-B I-A 5 3 C-A I-B 12 10 C-B C-A 3 5 I-A C-B 10 12 I-B GND 8 8 GND 3. V.24 / V.28 bit timing cable - (25 way to 25 way D type plugs).
Appendix E - Private digital circuits AM64/128A User Manual 5. X.21 bis V.36 bit timing cable - (37 way to 37 way D type plugs).
AM64/128A User Manual Appendix F - Troubleshooting Appendix F - Troubleshooting Please check the following points if problems are encountered when setting up a BBM link. 1. Ensure the modem is being used on unconditioned copper twisted pair wire. 2. Check one modem is set to Master and the other modem is set to Slave. 3. Check line rate is set correctly at each modem (64K Rate or 128K Rate). This setting has to be made at each end of a link - it cannot be downloaded from Master to Slave unit. 4.
Appendix F - Troubleshooting AM64/128A User Manual In some environments, the external timing input (SEXT on X.21 or circuits 113 on the X.21 bis interfaces) of an AM64/128A set in Master Mode may become sensitive to external coupled noise. This may have the effect of pulling the modem’s VCO (internal oscillator) off to one side and causing a normal Master to Slave Baseband link to lose synchronism.
AM64/128A User Manual
