AT&T MERLIN LEGEND Release 2.0 Equipment And Operations Manual page 237

Data Communications Support
Ricoh fax models on the communications system. The communicating adjunct
is the 7500B Data Module, (see Chapter 2 for a description of the 7500 Data
Module).
Group IV (G4) Fax machine are available from a number of manufacturers, each
of whom uses proprietary interface connections. One manufacturer may even
use different interfaces as standard from one model to another. Some require
the buyer to specify various CCITT versions for the standard EIA-RS-232
interface, for example, V. 11, V.28, or V.35. In most cases, these interfaces are
simple plug-in connections and are off-the-shelf items. It is important to know
before buying the fax machine what interfaces are required. This also means
knowing the transmission type the machine normally operates in, asynchronous
or synchronous. (When operating behind the communications system, it is
operates synch ronously.)
Fax Configuration 1: Direct RS-232 Interface
This is the recommended connection. The other two methods, described later,
are shown as alternatives when the EIA interface on the fax machine requires
that they be used. The communications system does support the three
methods, but there is virtually no advantage of using one method over another;
it is only a matter of which interface the fax machine uses.
Figure 5-2 shows the configuration for a direct RS-232 interface, a synchronous
DTE-to-synchronous DCE configuration that includes communication between a
7500B Data Module and a Group IV (G4) fax machine.
PRI Applications 5-19