User Guide
Servicing Information
91
RS530 / RS422 Null-Modem Cable
Shield
Transmitted Data (A)
Transmitted Data (B)
Received Data (A)
Received Data (B)
Request To Send (A)
Request To Send (B)
Clear To Send (A)
Clear To Send (B)
DCE Ready (A)
DCE Ready (B)
DTE Ready (A)
DTE Ready (B)
Signal Ground
Received Line Signal Detector (A)
Received Line Signal Detector (B)
Transmit Timing (A) DCE Source
Transmit Timing (B) DCE Source
Receiver Timing (A) DCE Source
Receiver Timing (B) DCE Source
Local Loopback
Remote Loopback
Transmit Timing (A) DTE Source
Transmit Timing (B) DTE Source
Test Mode
Clear To Send (A)
D
B
2
5
M
A
L
E
1
2
14
3
16
4
19
5
13
6
22
20
23
7
8
10
15
12
17
9
18
21
24
11
25
D
B
2
5
M
A
L
E
1
3
16
2
14
6
22
5
13
4
19
8
10
7
20
23
24
11
17
9
18
21
15
12
25
Transmitted Data (A)
Received Data (A)
Transmitted Data (B)
Received Data (B)
DCE Ready (A)
DCE Ready (B)
Clear To Send (B)
Request To Send (A)
Request To Send (B)
Received Line Signal Detector (A)
Received Line Signal Detector (B)
DTE Ready (A)
DTE Ready (B)
Signal Ground
Transmit Timing (A) DTE Source
Transmit Timing (B) DTE Source
Local Loopback
Remote Loopback
Receiver Timing (A) DCE Source
Transmit Timing (A) DCE Source
Transmit Timing (B) DCE Source
Test Mode
Shield
Receiver Timing (B) DCE Source
Figure C-13 RS530 / RS422 Null-Modem Cable
The connecting cable must be a shielded cable.
Circuits which are paired (contain an (A) and (B) reference)
should be connected to twisted pairs within the connecting cable.
This cable is needed when it is necessary to connect two units back-to-
back and a set of modems is not available. Note that this cable
specifies DB25 connectors on each end to allow direct connection to
the link interface connector on each unit. The link speed must be
defined for each of the two units.