ATL AM2048 User Manual

User Guide

AM768A

AM2048A MP

AM2048A CAP

AM2048A OS/M

Ascom Telecom

1/187/500/610

Issue 8 - Dec 2001.

Part Number :

ascom telecom

USER GUIDE AM768A/AM2048A

THE INFORMATION CONTAINED IN

THIS DOCUMENT IS CONFIDENTIAL TO

ascom TELECOMMUNICATIONS LTD. AND MAY

NOT BE DISCLOSED OR REPRODUCED IN WHOLE

OR PART WITHOUT THEIR WRITTEN CONSENT.

ascom TELECOMMUNICATIONS LTD. 2001

Issue 8

ascom telecom

USER GUIDE AM768A/AM2048A

Note:

Ascom Telecommunications Limited reserves the right to make changes to this

Compliance Notes and Safety Instructions:

The information contained in this document is supplied without liability for errors or omissions.

document at any time without notice.

Caution – Hazardous voltage inside the equipment Safety Instructions:

This apparatus must be installed and maintained by SERVICE PERSONNEL. Disconnect the mains plug and the NTP line connection before attempting to change the user interface plug-in module. The mains plug on the equipment serves as the disconnect device, therefore a socket outlet shall be installed near the equipment and shall be easily accessible.

Power Rating Information – AC plug top adapter:

Voltage Range 240V – 10% +6% Current Range 25mA to 50mA Frequency Range 50/60Hz

Power Rating Information – 240V AC in-line adapter: Voltage Range 240V – 10% +6% Current Range 25mA to 50mA Frequency Range 50/60Hz

Power Rating Information – 110V AC in-line adapter: Voltage Range 110V – 10% +6% Current Range 50mA to 100mA Frequency Range 50/60Hz

Power Rating Information – DC Source: Voltage Range 40.5V to 58V Current Range 70mA to 200mA

TTE – Network Statement

Safety Statements

The copper DSL line connection has a safety status of TNV-3

The Plug Top DC Power connection has a safety status of TNV-2 The X.21 Digital Network Interface Port has a safety status of SELV The V.35 Digital Network Interface Port has a safety status of SELV The 10/100 BaseT Port has a safety status of SELV.

For the G.703 Port Connection to Unexposed Environments:

The Alarm Port has a safety status of SELV. The G.703 Digital Network Interface Port has a safety status of SELV

For the G.703 Port Connection to Exposed Environments:

The Alarm Port has a safety status of earthed SELV. The G.703 Digital Network Interface Port has a safety status of TNV-1

The Protective Earth on the rear panel MUST be connected (see Section 4 on

Installation)

Issue 8

ascom telecom

Definitions: Exposed Environment

A TELECOMMUNICATIONS NETWORK is considered to be an exposed environment if one or more conditions for an unexposed environment are not fulfilled.

Unexposed Environment

A TELECOMMUNICATIONS NETWORK is considered to be an unexposed environment if the following conditions apply to all parts of the network

a) The possible effect of indirect lightning has been reduced by measures described

in IEC 61312-1.

b) The possibility of having different earth potentials has been reduced by

connecting all equipment within the network to the same equipotential bonding

system (see HD 384). c) The possibility of power cross/contact has been reduced (see HD 384). d) The possibility of induced transients and voltages has been reduced.

Caution – Laser Product

The Optical Interface is classified as a CLASS 1 LASER PRODUCT.

USER GUIDE AM768A/AM2048A

Caution – Electrostatic sensitive device

Electro-static discharge (ESD) Warning:

Antistatic precautions should be observed at all times.

If the unit is power fed from the DSL line interface then a functional earth MUST be

connected. (See Section 4 on Installation)

EMC Statement

This is a Class A product. In a domestic environment this product may cause radio interference in which case the user may be required to take adequate measures.

Manufacturers Declaration*

Ascom Telecommunications Limited declares that this product is in conformity with the essential requirements of the ‘R&TTE directive 1999/5/EC’.

* A copy of the Declaration of Conformity is available upon request from Ascom Telecommunications Ltd.

Issue 8

ascom telecom

USER GUIDE AM768A/AM2048A

Contents

COMPLIANCE NOTES AND SAFETY INSTRUCTIONS:...................................3

1. INTRODUCTION........................................................................................................................................7

2. CONSTRUCTIONAL DETAILS................................................................................................................8

3. SYSTEM OVERVIEW..............................................................................................................................10

3.1 COPPER TRANSMISSION.........................................................................................................................10

3.2 OPTICAL TRANSMISSION .......................................................................................................................11

3.3 DSL TRANSMISSION FRAME .................................................................................................................12

3.4 CONTROL CIRCUIT.................................................................................................................................12

3.5 ALARM INTERFACE ...............................................................................................................................13

3.6 USER INTERFACE MODULES ..................................................................................................................13

4. INSTALLATION.........................................................................................................................................14

4.1 CONNECTION OF PROTECTIVE EARTH....................................................................................................14

4.2 POWER ON SEQUENCE...........................................................................................................................14

4.3 LOGGING ON .........................................................................................................................................14

4.4 SETTING MASTER/SLAVE MODE............................................................................................................ 15

4.5 SETTING THE USER INTERFACE .............................................................................................................15

4.6 SETTING THE NX64K USER DATA RATE ...............................................................................................16

4.7 SELECTING THE CIRCUIT CONFIGURATION............................................................................................16

4.7.1 Point to Point Link........................................................................................................................ 17

4.7.2 Point to Multipoint Link................................................................................................................20

4.8 BRINGING INTO SERVICE .......................................................................................................................22

4.9 TRANSMISSION PARAMETERS................................................................................................................23

4.9.1 Transmission Range......................................................................................................................23

4.9.2 End to End Delay..........................................................................................................................24

4.9.3 Jitter..............................................................................................................................................24

4.10 G.703 INTERFACE OPTIONS...................................................................................................................25

4.10.1 Unstructured Operation................................................................................................................25

4.10.2 Structured Operation....................................................................................................................26

4.10.3 Structured Working, CRCs Enabled.............................................................................................27

4.10.4 ETS 300 233 Loopbacks ...............................................................................................................28

5. PHYSICAL INTERFACES .......................................................................................................................30

5.1 MAINS POWER SUPPLY..........................................................................................................................30

5.1.1 240V Plug Top PSU......................................................................................................................30

5.1.2 240V In Line PSU.........................................................................................................................30

5.1.3 110V In-line PSU..........................................................................................................................30

5.2 DC POWER INLET ..................................................................................................................................30

5.3 COPPER TRANSMISSION LINE ................................................................................................................31

5.4 OPTICAL TRANSMISSION LINE...............................................................................................................31

5.5 SERIAL CONTROL ..................................................................................................................................31

5.6 ALARM INPUT/OUTPUT PORT ................................................................................................................32

5.7 INTERFACE MODULES ...........................................................................................................................33

5.7.1 G.703 ............................................................................................................................................33

5.7.2 X.21...............................................................................................................................................34

5.7.3 V.35...............................................................................................................................................35

5.8 FRONT PANEL........................................................................................................................................36

5.8.1 Controls........................................................................................................................................36

5.8.2 Indicators...................................................................................................................................... 37

Issue 8

ascom telecom

USER GUIDE AM768A/AM2048A

6. INTERNAL LINKS AND FUSES..................................................................................38

6.1 G.703 PLUG IN MODULE....................................................................................................................... 38

6.2 X.21 PLUG IN MODULE MK I................................................................................................................38

6.3 X.21 PLUG IN MODULE MK II..............................................................................................................39

6.4 V.35 PLUG IN MODULE (MK I AND MK II)...........................................................................................39

6.5 MOTHERBOARD.....................................................................................................................................40

7. COMPLIANCE NOTES ..............................................................................................................................41

7.1 TELECOMMUNICATION STANDARDS......................................................................................................41

8. GLOSSARY................................................................................................................................................42

9. TROUBLESHOOTING.............................................................................................................................44

APPENDIX A - X.21/V.35 CABLE LENGTHS...............................................................................................45

X.21 CABLES - POTENTIAL PROBLEM LENGTHS ...............................................................................................46

V.35 CABLES - POTENTIAL PROBLEM LENGTHS ...............................................................................................48

APPENDIX B – ORDERING INFORMATION .............................................................................................50

Issue 8

ascom telecom

USER GUIDE AM768A/AM2048A

1. Introduction

This manual applies to the High Speed DSL Systems, designed and manufactured by Ascom Telecommunications Ltd in the U.K..

The modems provide synchronous communications at user data rates between 64kbps and 2048kbps over up to three twisted pair cables or a single optical fibre. The equipment has modular transmission and user interfaces, which allows the equipment to be configured to meet many different installation requirements. Both rack and desktop versions of all units are available. Desktop units are AM2048A… and rackmount units are AM2048B… This manual covers the desktop units.

The AM2048A OS provides full duplex transmission at 2.048Mbps over a single single-mode optical fibre.

The AM2048A OM provides full duplex transmission at 2.048Mbps over a single multi-mode optical fibre.

The AM2048A MP provides full duplex transmission at 2.048Mbps using 3 copper pairs. It can be used in point to point or point to multipoint mode. The line code is 3B1O.

The AM2048A CAP provides full duplex transmission at 2.048Mbps using 1 or 2 copper pairs. It can be used in point to point or point to multipoint mode. The line code is CAP.

The AM768A is a reduced cost unit, available with a single transmission module. This has most of the functionality of the AM2048 but reduced payload bandwidth due to using one transmission line instead of three. It is intended mainly for use in point to multipoint mode in conjunction with the AM2048A MP or the AM2048B MP

Separate interface modules can also be purchased in order to modify the units for operation with a different terminal interface at a later date.

Throughout the handbook, all types of unit are referred to as DSLU (Digital Subscriber Line Unit)

The DSLU can easily be configured via a dumb terminal. It is recommended to use a VT100 terminal emulation program running on a notebook or palmtop PC. Using the menu system with on-line help should reduce the need to refer to the handbook.

Once configured, the operation of the DSLU is totally automatic. In the event of line disturbances or power failure, the data link is restored without operator intervention.

Chapter 4 (Installation) describes the basic set up procedure and this should be read prior to setting up any link.

The VT100 Management User Guide gives a full description of the menu system..

Modifications to line cords and power supply leads are available for country specific requirements. In such cases, the line cord pinout may be different. The basic model is the same, line cords and power cords are separate plug in items.

Issue 8

ascom telecom

2. Constructional Details

USER GUIDE AM768A/AM2048A

Figure 1 Desktop Unit

The desktop unit is housed in a grey non-flammable plastic case (UL94 rating V0). The membrane front panel contains 5 LED indicators and 3 push button switches with LEDs to indicate their activation.

LEDs

• Urgent Alarm

• Non Urgent Alarm

• Test

• Power

• Master

Buttons

• Local Loop

• Loop Back

• Rem Loop

Issue 8

ascom telecom

USER GUIDE AM768A/AM2048A

On the rear panel there are the following connectors: –48V DC supply inlet socket 3-pin mini-fit line interface 8 way RJ45 (Copper)

FC/SPC (Optical) See Appendix B for other options. Management port interface 9 way female D-type Alarm interface 13 way circular DIN Data Ports (depending on module fitted)

G.703 120Ω 8 way RJ45 G.703 75Ω BNC X.21 15 way D-type female V35 34 way MRAC female

The data interface connector type will be from one of the three user specified interfaces available. They are detailed in section 5. The plastic housing contains the main PCB. The plastic case has an internal metallised layer for EMC screening purposes. The membrane front panel is attached to the main PCB with a flexible circuit connector.

Also included is a 3 metre screened, stranded, Category 5 line cord terminated in 8-way RJ45 plugs at both ends.

Optional plug-top and in-line mains adapters are available with a 1.8 metre long DC lead, terminating in a 3-pin mini-fit plug. Also available is a VT100 Management connection cable.

The overall dimensions of the unit are 274mm(L) x 251mm(W) x 55mm(H).

Issue 8

ascom telecom

3. System Overview

USER GUIDE AM768A/AM2048A

Transmission Modules

User Interface Module

G703

75/120

ohms

Primary Rate

Interface

Micro

Controller

ascom

HDSL

Interface

Chip

Figure 2 Copper System Block Diagram

DSP Chip

Transceiver

Analogue

Interface

Transceiver

Analogue

Interface

Transceiver

Analogue

Interface

Pair 1

Pair 2

Pair 3

3.1 Copper Transmission

The copper system is intended for operation on 2-wire local telephone network circuits, such as those meeting BT EPS-9 (Note: the DSLU requires between one and three such circuits). It will operate satisfactorily on unloaded lines having a wide range of characteristics; bridge taps can be tolerated, dependent upon their characteristics. Although, the system requires a baseband circuit, a continuous loop at DC is not required. The system can transmit data at rates between 64k and 2048k.

For the copper system, echo cancellation is used to eliminate the unwanted reflections of the transmitted signal from the receiver input.

The line is connected to the transmission circuit via a line transformer, which acts as a balun and provides isolation; there is surge protection across the transformer line connections. The transmission circuit utilises a custom IC and a number of proprietary components to perform the signal processing described above.

When more than one transmission line is in operation, each transmission system operates with the same bit rate derived from an oscillator in the master unit.

Issue 8

ascom telecom

User Interface Module

USER GUIDE AM768A/AM2048A

Optical Transmission Module

Laser Driver

G703

75/120

ohms

Primary Rate

Interface

Micro

Controller

ascom

HDSL

Interface

Chip

ascom

Tranceiver

Codec

Chip

Clock

Recovery

Optical

Duplexer

Analogue Rx

and

Channel

Separation

Filter

Figure 3 Optical System Block Diagram

3.2 Optical Transmission

The optical transmission interface module fits into the same envelope as three copper modules and is designed to operate over a single optical fibre. This is accomplished using an optical duplexer, which integrates a laser and a photodiode in a single package. Both directions are transmitted at the 1310nm optical window, leaving the 1550nm window free. The interface module encodes the DSL framed data using a 5B6B block code for error monitoring and spectral shaping. Sub-carrier modulation is used to increase the separation between the upstream and downstream directions. Baseband transmission is used from ELU to NTU, whereas the other direction is modulated onto a carrier.

For transmission over single-mode fibre, order the AM2048 OS. For transmission over multi-mode fibre, order the AM2048 OM.

The AM2048A OS and AM2048 OM are Class I products in accordance with EN60825-1 and therefore inherently safe.

Issue 8

ascom telecom

USER GUIDE AM768A/AM2048A

3.3 DSL Transmission Frame

Both of the above transmission systems operate in a bit pump mode. The DSL frame is sent over this ‘data pipe’. The DSL frame contains the following

• Sync word

• Stuff bits

• Stuff control bits

• EOC channel

• Customer data

The nominal DSL frame is always 6ms long, regardless of the transmission rate of the individual channels.

The DSL frame length is adjusted slightly by the use of stuff bits. There may be 4 stuff bits or 2 stuff bits per frame. The stuff bits are used to adjust the effective payload bandwidth of the DSL frame.

If the user rate clock is slightly quicker than the line rate clock then less stuff bits are sent. Alternatively, if the user rate clock is slightly slower than the line rate clock then more stuff bits are sent. This mechanism allows the line rate bandwidth to be adjusted to match the user rate bandwidth.

At the receive end, the rate at which the stuff bits arrive is used to recover the user clock.

The transmit and receive paths may be operated independently from one another so that when a G.703 user interface is present, the transmit and receive clocks are allowed to vary independently by

50ppm. (Note. When operating with X.21 or V.35 interfaces, there is only a single clock at each user

+ interface.)

The Embedded Operation Channel (EOC) is carried in spare overhead bits in the transmission frame. Packetised SNMP SET and GET messages are passed over the link from the ELU to the NTU, which answers with the appropriate SNMP response.

Byte timing is maintained by the transmission system and is available if required.

3.4 Control Circuit

The control circuit is based on a micro-controller and determines the operational status of the unit according to the state of the transmission system, the data interface and the configuration information received from the terminal.

Configuration data and two copies of the application are stored internally in FLASH memory. On power-up the application program is copied from FLASH to RAM from where it is executed. The main application program is backed up so that if a corruption occurs it can be corrected. This also enables the programming of a new application while the equipment is operating normally. Control is transferred to the new application after an automatic restart at the end of the download. This minimises the interruption of payload traffic. Also, if programming is interrupted, the previous version of software will remain intact. A new application program may also be downloaded from the ELU to the remote NTU over the line.

Issue 8

ascom telecom

USER GUIDE AM768A/AM2048A

3.5 Alarm Interface

A 13 pin circular DIN connector provides access to 6 alarm inputs that are used to detect metallic contact closure. For example, they can be used to sense a cabinet door open or temperature sensors. The priority of these auxiliary alarms may be programmed through the “Alarms>Severity Level Settings” screen.

There are also relay contact outputs to indicate urgent and non-urgent alarms. This allows the system to be easily integrated into the alarm systems of other equipment.

3.6 User Interface Modules

The user interface is provided by a plug-in module of which there are six types:

• G.703, with software selectable 75ohm or 120ohm ports

• X.21

• V.35

• G.703 MK II (with 1 + 1 protection switch)

• X.21 MK II (with tail buffer)

• V.35 MK II (with tail buffer)

The existing interface module can be changed out using a pluggable replacement unit. These can be ordered separately using the part numbers detailed below. For part numbers and order codes see Appendix B.

Issue 8

ascom telecom

USER GUIDE AM768A/AM2048A

4. Installation

This chapter describes the basic steps that are required to set up a system involving the DSL Modem.

4.1 Connection of Protective Earth

If it is required to connect the G.703 port to a circuit that is defined as TNV, then a protective earth must be connected to the earth bond stud on the rear panel. See the Compliance Notes and Safety Instructions inside the front cover.

If the unit is power fed then a functional earth must be connected to the earth bond stud on the rear panel to provide a discharge path to ground for ESD protection. See the Compliance Notes and Safety Instructions inside the front cover.

4.2 Power On Sequence

With no DTE or line connected to the DSLU on power up, the following LED sequence will be displayed:

2345678 9 10

Urgent

Non-Urgent

Test

Power

Prior to the sequence starting, a random pattern may appear momentarily. During sequence 1 to 7 the LEDs are illuminated in turn as an LED confidence test. During stage 8 the test LED flashes as the internal self-test sequence is completed. The flashing will normally last for about 4 seconds, however, if a new application has been loaded this time will be extended by about 10 seconds while a backup copy of the application is made. With no external connections the unit will sense the loss of external signals, raise the urgent alarm and stop at stage 9. When the system has been installed and is working correctly, the unit should move to stage 10.

4.3 Logging On

Connect a VT100 terminal (or PC running a VT100 emulation program) to the 9-way serial port on the rear of the unit. The log on screen should appear automatically once the DSLU detects the terminal. Type ‘C’ to select Configuration, then press ‘Enter’ Type ‘ascom’ the default password setting, then press ‘Enter’ The top level menu system displays the sub-menus available. For a full description of the menu system, refer to the ‘VT100 Management User Guide’.

Issue 8

ascom telecom

USER GUIDE AM768A/AM2048A

4.4 Setting Master/Slave mode.

For all modes of operation, one unit must be set to master mode, while the other unit is set to slave mode. The master unit is referred to as the ELU or Exchange Line Unit and the slave unit is referred

to as the NTU or Network Terminating Unit. The front panel ‘Master’ LED indicates the mode of the unit.

The ELU is a ‘master’ in several senses. The master end provides the source of the bit rate timing for the transmission line(s). The ELU is also the ‘master’ from a network management point of view. It contains the database of configuration information for itself and all connected NTUs. The alarm and performance monitoring history is saved at the ELU. When the management terminal is connected to the ELU it can read all of the information from the remote NTU, whereas when the management terminal is connected to the NTU, only the local information is obtainable.

The factory default is for the unit to be configured as a slave (NTU).

To change the setting, using the terminal go to the “Configuration>Master/Slave” screen and select the appropriate option. (use the arrow keys or tab key to navigate and the spacebar to change the setting). The basic setup for all modes is as follows:

At the master end: Configuration>Master/Slave

1. select Master.

2. select Point- to Point or Point to Multipoint, as appropriate.

3. enable the required number of lines

At the slave end: The factory default setting should allow the units to get into sync, otherwise: Configuration>Master/Slave

4. select Slave.

5. select Point- to Point or Point to Multipoint, as appropriate.

6. enable the required number of lines

The unit will automatically reboot with the new settings once the “return” key is pressed to accept the changes. You will then be invited to log back on to the system.

It is possible to set Master/Slave by using the front panel buttons if a terminal is unavailable, see section 5.8.1.

4.5 Setting the User Interface

The unit automatically detects what kind of user interface is plugged in and displays the appropriate screen in the “Configuration>User Port” screen.

For X.21 and V.35, DTE/DCE selection is carried out by moving the link header on the user interface plug-in module. The software automatically senses the link setting and sets the unit up accordingly.

To check the user interface and any link settings, using the terminal, go to the “Information>System” screen, this will display which user interface has been plugged in, and which mode it is in.

Once a unit is configured as an ELU, the expected interface at the NTU may be set, or by default, the unit will auto-discover the NTU user port configuration after the line gets into synchronisation.

Issue 8

ascom telecom

USER GUIDE AM768A/AM2048A

4.6 Setting the Nx64K User Data Rate

For X.21 and V.35 the data rate may be set in increments of 64kbps. The default setting of N = 6. The data rate is set by entering the desired value of N. The full range of N is from 1 to 32. The screen display gives the equivalent data rate in kbps for the value of N. The software automatically restricts the value of N to match the user interface and line interface combination. e.g. for an Am768, the maximum value of N = 12.

For a G.703 to Nx64 configuration, the maximum value of N is 31 as only timeslots 1 to 31 are transported over the transmission link. N may be further restricted depending on the transmission system.

For software up to version 2.9

At the master end: Configuration>User Port

1. Set the desired value of N.

2. Press F8, to select the remote end

3. Set the desired value of N

4. Press Enter to activate the change.

For software versions greater than 2.9

At the master end: Configuration>User Port

1. Set the desired value of N.

2. Press Enter to activate the change.

, the value of N must be entered for each end of the link as follows:

, the value of N only needs to be set once:

4.7 Selecting the Circuit Configuration

The term ‘digital section’ refers to the data link between the user ports of the connected DSLUs. In a standalone section, the DSLUs provide the complete transmission system. In a tandem section, the DSLUs are used to extend an existing circuit or network port. To achieve synchronous data transfer, the master DSLU must derive its timing from the circuit to which it is connected. A Point to Point link requires two DSLUs, one master and one slave. A Point to Multipoint link can have up to four DSLUs, one master and up to three slaves. The DSLU at one end of the digital section is selected to be a Master (ELU), the remote end(s) are selected to be slave(s) (NTUs). For a tandem section, the DSLU connected to the tandem section is configured as the master. Please refer to the diagrams on the following pages.

Issue 8

+ 35 hidden pages

ATL AM2048 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual