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ATL AM64/128A User Manual

Base band modem
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AM64/128A
BASE BAND MODEM

USER MANUAL

ATL Part No. 1/203/002/610
Issue 4 - September 2002.

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  • Page 1: User Manual

    AM64/128A BASE BAND MODEM USER MANUAL ATL Part No. 1/203/002/610 Issue 4 - September 2002.
  • Page 2 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.

  • Page 3: Table Of Contents

    Contents AM64/128A User Manual CONTENTS Introduction ........... . .5 Constructional Details .
  • Page 4 AM64/128A User Manual Contents Option Menu ..........30 5.6.1...

  • Page 5: 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 :- •...

  • Page 6: Constructional Details

    Constructional Details AM64/128A User Manual CONSTRUCTIONAL DETAILS Baseband Modems 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.

  • Page 7: System Overview

    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;...
  • Page 8 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.

  • Page 9: Installation

    Installation 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.
  • Page 10 64kbps. In this configuration, the unit will extract its timing from the G.703 interface and passes it to the Slave end of the link. It is NOT possible for the AM64/128A (set to Slave mode) to have a G.703 Interface fitted.

  • Page 11: Bbm To Line Card Link

    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.

  • Page 12: Menu Operation

    Menu Operation AM64/128A User Manual MENU OPERATION 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.

  • Page 13: Front Panel Operation

    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: STATUS (Prompt is S>) TEST (Prompt is T>) RATE (Prompt is R>) OPTION (Prompt is O>) CONFIG (Prompt is C>)

  • Page 14: Status Menu

    Status Menu 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: Overall status Alarm messages User data rate Line rate Interface status Operating mode 5.3.1 Over all Status The possible messages for this item in priority order, and the conditions which set them are as follows: S >...

  • Page 15: Alarm Status

    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.

  • Page 16: User Rate

    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.

  • Page 17: Mode Display

    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.

  • Page 18: Test Menu

    Menu Operation - Test Menu AM64/128A User Manual Test Menu 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.

  • Page 19: Loopback

    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.

  • Page 20: Remote Loop

    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.

  • Page 21: Binary Patterns

    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.

  • Page 22: Data Test

    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.
  • Page 23 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.
  • Page 24 Test Menu AM64/128A User Manual 2/ Pattern display Injecting 0s The pattern display usually shows Injecting 1s Pressing SELECT will cause binary 1s to be injected (e.g. for loop verification): This pattern will continue to be injected until the SELECT key is pressed again, (or the mode is exited).

  • Page 25: In Service Test

    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.

  • Page 26: Lamp Test

    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.

  • Page 27: Communications Channel Loop Back

    AM64/128A User Manual Test Menu However, the usage of the EEPROM (Blocks Used) is still displayed for information. For example: means that the first block is in use and that there are 254 empty blocks. means that the last block is being used and the chip is nearly full.

  • Page 28: Rate Menu

    Menu Operation - Rate Menu 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.
  • Page 29 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;...

  • Page 30: Option Menu

    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 X.21, X.21bis or G.703...

  • Page 31: Asynchronous Mode

    AM64/128A User Manual Menu Operation - Option Menu O > 107 Normal Press SELECT: O > 107=108/1 This allows control line 107 to follow control line 108/1 independent of other factors. O > 108/1 Normal O > 108/1 Set On Press SELECT This option holds the control line 108/1 ON internally.

  • Page 32: Character Length

    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.

  • Page 33: Configuration Menu

    AM64/128A User Manual 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 non- volatile memory and are restored each time the BBM is powered up.

  • Page 34: Loop Control

    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. slave master Modem Modem Modem Modem To DTE X2.1 Link...
  • Page 35 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.

  • Page 36: Mode

    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.

  • Page 37: Glossary Of Terms

    AM64/128A User Manual Glossary GLOSSARY OF TERMS Alarm Indication Signal. Automatic Local Test. - Pattern sent to apply a local loop in the DCE. Alternate Mark Inversion. - Code used for line transmission. Automatic Remote Test. - Pattern sent to apply a loopback on the remote modem.
  • Page 38 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.

  • Page 39: General 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.

  • Page 40: Appendix A Interface Pin Connections

    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).
  • Page 41 (using both A and B wires) or unbalanced single ended circuits. In the case of the control circuits the A wire is to be used and the B wire is to be joined to GND (circuit 102) at the receiver end of the circuit. In the AM64/128A circuit 105 is implemented as a balanced circuit and 106,107,109 are unbalanced.
  • Page 42 B wires) or as an unbalanced single ended circuit. In the AM64/128A, circuit 105 is implemented as a balanced circuit and 106,107,109 are unbalanced. To allow inter working between balanced and unbalanced circuits, the A wire is to be used and the B wire is to be joined to GND (circuit 102) at the receiver end of the circuit.

  • Page 43: Appendix B Internal Link Settings

    Appendix B – Internal Link Settings AM64/128A User Manual APPENDIX B – Internal Link Settings...
  • Page 44 AM64/128A User Manual The function of the links is as follows: Transmission disable This link is always left in position 1-2 Watch dog enable This link is always left in position 1-2 This connects the supply earth to the circuit ground in position 1-3...
  • Page 45 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.
  • Page 46 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.

  • Page 47: Appendix C In Service Test

    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.
  • Page 48 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.

  • Page 49: Appendix D Approvals

    Manufacturers Declaration* ATL Telecom Ltd declares that this product is in conformity with the essential requirements of the 'R&TTE directives 1999/5/EC' * A copy of the Declaration of Conformity is available upon request from ATL Telecom Ltd. A-10...

  • Page 50: Appendix E Use On X.21/X.21Bis Digital Circuits

    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.
  • Page 51 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 SEXT-A SEXT-B 3. V.24 / V.28 bit timing cable - (25 way to 25 way D type plugs).
  • Page 52 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). CCITT circuit Timing Source (DCE) Timing Sink (DTE) CCITT circuit 103-A 104-A 103-B 104-B 104-A...

  • Page 53: Appendix F Troubleshooting

    BBM. A special cable may need to be made for external timing applications, as per Appendix E. 9. Check both modems are operating in Link Mode (last item in the Status Menu) for a BBM to BBM link. 10.Check that the External Element Timing Inputs of AM64/128A set in Master Mode: A-15...
  • Page 54 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.
  • Page 55 AM64/128A User Manual...

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