Avaya 03-300430 User Manual

The MPDM provides an interface for Data Terminal Equipment (terminals), and the MTDM (see 
Note) provides an interface for Data Communications Equipment (transmission equipment such 
as modems).

Note:

Early versions of these data modules were referred to as PDMs and TDMs, 
respectively. Later models are designed to provide various customer interfaces 
through the use of interchangeable interface modules and, therefore, are called 
modular data modules. Both versions are supported by the tests described in this 
section.

In the following discussion, the general term data module refers to MPDMs, MTDMs, and DAs. 
The PBX loop or digital link between a data module and the Digital Line port supports two logical 
information channels and one signaling channel. Data modules generally use the primary 
information channel for data communications and the signaling channel for dialing and call 
supervision. With 4-wire DCP, the secondary information channel can be used to support a 
second data module on a shared port.
Besides being used for data calls between terminals, computers, and data communications 
equipment, data modules also serve as interfaces to equipment associated with system 
features such as System Administration, Station Message Detailed Recording, Message Center 
Service, Automatic Call Distribution, Distributed Communications System, and Audio 
Information Exchange. Maintenance for data modules associated with these latter services are 
covered by other MOs such as PMS-PRNT, JNL-PRNT, and PMS-LINK.
Maintenance of data modules is closely related to and interacts with Digital Line circuit pack 
maintenance, and test results for data modules can be affected by the health of the Digital Line 
circuit pack. Keep this interaction in mind when investigating customer-reported problems with 
data modules.
Data modules provide a variety of option switches to allow the customer to select data rates, 
parity, keyboard dialing, local, and remote loop back, etc. (The DAA2 Data Adaptor has an AT 
(Hayes) type interface that allows selection of the above parameters as well as mode linked or 
stand-alone.) An incorrect selection will not necessarily cause errors, alarms or test failures, but 
it can result in service disruption. See the installation manual provided with the data module for 
more information about those options.
This discussion occasionally refers to a station’s service state, defined as:

Out-of-Service

The port, and thus the data module, have been removed from 

service. Causes for this include busyout of the port, removal of the 

Digital Line circuit pack and failure of the NPE Crosstalk test (#9).