Connection From Gc Controller To External Modem; A.3.1 Db-9 Serial Port Of Gc To Db-25 Port Of Modem - Emerson Daniel Danalyzer 1000 Hardware Reference Manual

SEP 2005
A.3 RS-232 CONNECTION FROM GC CONTROLLER TO EXTERNAL MODEM

A.3.1 DB-9 Serial Port of GC to DB-25 Port of Modem

To make an RS-232 serial connection between one of the DB-9 serial ports of the GC, and an
external modem with a DB-25 serial port, you will need to manufacture a cable. The cable will need
DB-9, male, and DB-25, male, plug cable ends as illustrated below (see Figure A-7).
Figure A-7. GC DB-9 Port to External Modem DB-25 Port
The DB-9 jack on the GC serial port is wired to appear like a Data Communications
Equipment (DCE). Therefore, you use a custom "null-modem" type cable, as shown above, to
make the connection between the GC and an external modem.
(GC serial ports were wired to appear as DCE so that a 'straight-through' serial cable could be
used, instead of a null-modem cable, for direct serial connection between the GC Controller
and the PC, which is Data Terminal Equipment [DTE].)
A-8
SUPPLEMENTAL WIRING GUIDE - SERIAL COMMUNICATIONS
MODEL 1000