Data modules and asynchronous data units
555-233-116
60 Issue 4 October 2002
* Circuits are not used for asynchronous operation. Outputs are clamped OFF and inputs are ignored.
Configuring the 7400A for data communications
equipment (DCE) applications
If you are not going to use the 7400A data module in a modem pool, proceed as
follows.
9 — Reserved for Testing +12 volts —
10 — Reserved for Testing -12 volts —
11 — Not used — —
12 CI Data Signal Rate Select (DCE Source) Output Input
13 CI2 Data Signal Rate Select 2 (DCE Source) — Input
14 — Not used — —
15 DB* Transmitter Signal Element Timing (DCE
Source)
Output Input
16 — Not used — —
17 DD* Receiver Signal Element Timing (DCE
Source)
Output Input
18 LL Local Loopback Input Output
19 CH2 Data Signal Rate Select 2 (DTE Source) — Output
20 CD (DTR) Data Terminal Equipment Ready Input Output
21 RL Remove Loopback Input Output
22 CE (RI) Ring Indicator Output Input
23 CH Data Signal Rate Select (DTE Source) Input Output
24 DA* Transmit Signal Element Timing (DTE
Source)
Input Output
25 TM Test Mode Output Input
Pin Name Function DCE DTE
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