DDA-4280:   2.048 Mbps (E1) G.703 Data Distribution Amplifier.


      Data regeneration with Jitter Attenuator.
      Front panel monitoring facility.
      Protection switching facility.
      External alarms and bypass.
      Redundant pair operation capability.
      Simple Network Management Protocol (SNMP) monitoring.


User Manual  


The DDA-4280 data distribution amplifier is intended for use with E1 data signals conforming to the ITU Rec. G.703. The DDA-4280 is primarily intended for use in pairs with a double width rear assembly for automatic path protection applications, although it is supplied as standard with its own rear assembly for stand-alone applications.

Four outputs are provided at the rear of the module with an additional output for monitoring purposes on the front panel. One output (O/P 1) is controlled by relays to provide a bypass signal from the input in the event of a power failure.

Indicators are provided on the front panel for:

            Data loss
            AIS detect
            Module in service (Main)
            Module in standby

Changeover inhibit and changeover request switches are provided on the front panel for use where modules are linked in pairs for redundancy. For this configuration the double width rear assembly is needed to link the logic sections of two modules.

When used as a distribution amplifier the DDA may be housed in any of IRT's standard Eurocard frames. When used in pairs for handshake operation only 3 RU chassis types may be used so that the double width rear assembly may be used.

The DDA-4280 is also equipped with Simple Network Management Protocol (SNMP) monitoring so that status and alarms can be remotely monitored and controlled via an Ethernet connection. This function is only available when the unit is housed in an IRT 4000 series frame fitted with an SNMP agent module.


In accord with ITU-T Rec. G.703 - see Electrical characteristics of G.703 signals.

Transformer coupled.
75 Ω terminated.

1 switched, 3 non-switched, regenerated, reclocked shaped outputs located on rear connection assembly and 1 located on front panel.
75 Ω source terminated.

Electrical characteristics:
Cable type
See G.703 Specification for 2.048Mb/s data rate.

Controls & alarms:
External changeover request
A ground applied to this input will emulate the operation of the front panel switch "Change Request".
Power failure
Contact to open circuit if power has failed.
General alarm
Contact to open circuit if Data Loss is detected OR AIS is detected.

Krone LSA plus.

Data loss.
AIS detect.
Module in service (Main).
Module in standby.

Power Requirements:
28 Vac CT (14-0-14) or ±16 Vdc.
Power consumption
< 4 VA.

Temperature range
0 - 50°C ambient.
Suitable for mounting in IRT 19" rack chassis types with input output and power connections on the rear panel.
Finish:             Front panel
Grey background, black lettering & red IRT logo.
                       Rear Panel
Detachable silk-screened PCB with direct mount connectors to Eurocard and external signals.
6 HP x 3 U x 220 mm IRT Eurocard.
Standard accessories
DDA-4280 rear connector assembly.
Optional accessories
ZDA-4300RH double rear assembly, for handshake connection of two DDA-4280's.


Due to our policy of continuing development, these specifications are subject to change without notice.