Specifications

General Information
2-16 Issue 11 December 1999
switch, a data module must be inserted to provide compatibility. The data module
provides the two-way data signal conversion and processing required between
different protocols. Figure 2-3 shows a simplified diagram of the components of a
typical data link.
Figure 2-3. Data Link Components
The connection between a data module and a data endpoint must always have a
DCE or DTE interface. If the endpoint is a DCE, the data module must present a
DTE interface to it. If the endpoint is a DTE, then the data module must present a
DCE interface. In general, modules are classified as DCE- or DTE-type according
to the kind of data endpoint to which they are connected.
Data modules are available to match a wide variety of data needs:
■ Asynchronous operation at data rates from 0.3-19.2 kbps and even, odd,
mark/space, zero/one or no parity options.
■ Synchronous operation at data rates of 0.3, 1.2, 2.4, 4.8, 9.6, 19.2, 56, and
64 kbps.
■ Half- or full-duplex operation and internal or external timing options at the
appropriate data rates.
The following data equipment is available with a DEFINITY G1, G2, and G3, a
DEFINITY ECS, System 75, and System 85:
■ 7400A Data Module — In DTE mode, works with asynchronous DCE in
the modem pool at data rates of 0.3-19.2 kbps, full-duplex. Supports both
Hayes-compatible and D-lead modems. In DCE mode, the 7400A has
Hayes
®
, Keyboard Dial or Answer-Only interface. Also works with
asynchronous DTE where rack mounting is needed. Takes the place of
MTDM or MPDM in asynchronous applications.
■ 7400B and 7400B Plus Data Modules — Works with asynchronous DTE
at data rates of 0.3-19.2 kbps, full-duplex. Can be used with most
7400-series DCP voice terminals for simultaneous voice/data or
Data
Endpoint
Data
Module
Data
Module
Data
Endpoint
DEFINITY
G1, G2, G3
System 75
or
System 85
Digital
Switch
RS-232C/D
V.35
RS-449
DCP
RS-232C/D
V.35
RS-449
DCP