Owner's manual

Choosing Module Features
Chapter 3
32
Pin Signal
2
3
4
5
7
transmit data
receive data
request to send
clear to send
ground
Refer to Table 2.A for a detailed listing of RS-232-C pin functions.
Table 2.A
RS232C
Connector Pin Functions
Pin
No
Signal Name
EIA
Circuit
Source Functions
2 T ransmitted Data BA DTE Data T ransfer to
1771DA (DCE)
3 Received Data BB 1771DA
(DCE)
Data T ransfer to DTE
4 Request to Send CA DTE T ells the 1771DA data is
transmitted.
5 Clear to Send CB 1771DA
(DCE)
T ells DTE that data is
transmitted. Enabled only
if pin 4 is Vdc (of f).
6 Data Set Ready CC 1771DA
(DCE)
T ells DTE that 1771DA
(DCE) is ready
.
7 Signal Ground AB  Common ground for all
signals thru interface port
on 1771DA.
8 Receive Line Signal
Detector
CF 1771DA
(DCE)
T ied to +12V dc
20 Data T erminal Ready CD DTE T ells 1771DA (DCE) that
DTE is ready . Must be
+V dc to send or receive.
Current Loop
Use the current loop for communicating up to approximately 500 cable
feet between your ASCII device and ASCII module. A current loop has
high immunity to errors caused by electrical noise, has no signal
attenuation, eliminates ground loops, and is low cost.
A current loop is a loop that carries current (generally 20mA) between
electronic equipment by means of a twisted pair of wires. A transmitting
device in the loop transmits digital signals by interrupting the current