15
© Sealevel Systems, Inc.
4021 Manual | SL9154 11/2021
Programming The ACB 56, Continued
Connector P3 Pin Assignments
RS-232 Signals
S
ignal
Name
Pin #
Mode
GND
Ground
7
RD
Receive Data
3
Input RS-232
CTS
Clear To Send
5
Input RS-232
DSR
Data Set Ready
6
Input RS-232
DCD
Data Carrier. Detect
8
Output RS-232
TD
Transmit Data
2
Output RS-232
RTS
Request to Send
4
Output RS-232
TXC
Transmit Clock
15
Input/Output RS-232
RXC
Receive Clock
17
Input RS-232
TSET
Transmit Signal Element
Timing
24
Output RS-232
DTR
Data Terminal Ready
20
Output RS-232
These assignments meet the EIA/TIA/ANSI-232E DTE Specification
V.35 Signals
Signal
Name
DB-25
V.35
Mode
GND
Ground
7
B
RDB RX+
Receive Positive
16
T
Input
RDA RX-
Receive Negative
3
R
Input
TXCB TXC+
Transmit Clock Positive
12
AA
Input
TXCA TXC-
Transmit Clock Negative
15
Y
Input
RXCB RXC+
Receive Clock Positive
9
X
Input
RXCA RXC-
Receive Clock Negative
17
V
Input
TDB TX+
Transmit Positive
14
S
Output
TDA TX-
Transmit Negative
2
P
Output
TSETB TSET+ TSET Positive
11
W
Output
TSETA TSET- TSET Negative
24
U
Output
CTS
Clear To Send
5
D
Input*
DSR
Data Set Ready
6
E
Input*
DCD
Data Carrier Detect
8
F
Input*
DTR
Data Terminal Ready
20
H
Output*
RTS
Request To Send
4
C
Output*
All modem control signals are single ended (unbalanced) with RS-232 signal levels.
