Connect data modules
Issue 4 October 2002 59555-233-116
Adjusting the control-panel d isplay on the 7400A
1. Adjust the contrast of the display so that you c an see it comfortably. Press
the ENTER/YES button. This steps you throu gh the available contrast
settings.
7400A data module, EIA RS-232 interface circuits
The data module communicates with other equipment through a configurable, 25-
pin RS-232 serial interface. DCE and DTE operation use different sets of pins and
assign different functions to some of the same pins. To avoid confusion later on,
please take a moment to review the differences. See the table below (the pins
most discussed in subsequent sections have be en emphasized).
D
T
R
D
S
RR
I
D
C
D
R
T
S
C
T
ST
DR
DHOME
POWER
TEST 0 0 —000—— DATA NEXT/NO BACK ENTER/YES
✹7400A Data Module ✹ ❍❍❍
0 0 —000—— DATA NEXT/NO BACK ENTER/YES
● ❍❍➜ ●
Push the button indicated by the arrow (➜)
Pin Name Function DCE DTE
1 — Not used ——
2 BA (TD) Transmitted Data Input Output
3 BB (RD) Received Data Output Input
4 CA (RTS) Request to Send Input Output
5 CB (CTS) Clear to Send Output Input
6 CC (DSR) Data Communication Equipment Ready Output Input
7 AB (SG) Signal Ground Common Common
8 CF (RLSD) Received Line Signal Detector Output Input
Continued on next page