1257 User Manual
Computer Interfaces 4-14
EADS North America Defense
Test and Services, Inc.
©
2001
Using the RS-232
Interface
Basic RS-232
Information
The RS-232 interface provides a simple way to control the 1257
from virtually any computer. Nearly every computer has a serial
(COM) port. The only extra hardware required is a serial cable.
This section gives information about connecting the 1257 to the
computer via serial cable, setting up the 1257 for serial port
operation, and communicating with the 1257 by using a terminal
emulation program.
Equipment Required
To use the RS-232 interface, you need an RS-232 data terminal or
a computer equipped with an RS-232 serial port, such as the COM
port of a personal computer. In addition, a shielded cable is
required for compliance with the radiated emissions standards
specified for the 1257. A shielded RS-232 cable, suitable for
connecting the 1257 to a computer, is available from EADS North
America Defense Test and Services:
RS-232 Cable, 10 feet (3 meters)
P/N 602248
DTE Versus DCE
All equipment with an RS-232 interface must be designed as either
Data Communications Equipment (DCE) or Data Terminal
Equipment (DTE), depending upon the end of the communications
link from which it will operate. Computers are usually DTE, and
modems are DCE. This allows a “straight-through” connection,
where connector pins 1, 2, 3, ... at one end connect to pins 1, 2, 3,
... , respectively, at the other end.
The 1257 is designed as DCE to facilitate direct connection to a
computer or data terminal (DTE). Connecting to a modem requires
a “null modem”, described in the section Connecting to a Modem.
Connecting to a
Computer or Data
Terminal
Electrical Connection
Using a shielded RS-232 cable, connect the nine-pin female
RS-232 connector on the 1257 rear panel to the RS-232 serial port
on the computer or data terminal. Refer to
Figure 4-3, Using the
RS-232 Interface
. A suitable cable is available from EADS North
America Defense Test and Services:
