RS530 Null-Modem Cable Configuration
Shield
TransmittedData (A)
TransmittedData (B)
ReceivedData (A)
ReceivedData (B)
Request ToSend (A)
Request ToSend (B)
Clear ToSend (A)
Clear ToSend (B)
DCEReady ( A)
DCEReady ( B)
DTE Ready(A)
DTE Ready(B)
Signal Ground
Received Line Signal Detector (A)
Received Line Signal Detector (B)
TransmitTiming (A) DCE Source
TransmitTiming (B) DCE Source
ReceiverTiming (A) DCE Source
ReceiverTiming (B) DCE Source
Local Loopback
RemoteLoopback
TransmitTiming (A) DTE Source
TransmitTiming (B) DTE Source
TestMode
ClearTo Send (A)
DB25M
A
LE
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
DB25M
A
LE
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
TransmittedData (A)
ReceivedData (A)
TransmittedData (B)
ReceivedData (B)
DCEReady (A)
DCEReady (B)
ClearTo Send (B)
RequestTo Send (A)
RequestTo Send (B)
Received Line Signal Detector (A)
Received Line Signal Detector (B)
DTEReady (A)
DTEReady (B)
Signal Ground
TransmitTiming (A) DTE Source
TransmitTiming (B) DTE Source
Local Loopback
RemoteLoopback
ReceiverTiming (A) DCE Source
TransmitTiming (A) DCE Source
TransmitTiming (B) DCE Source
TestMode
Shield
ReceiverTiming (B) DCE Source

Figure D-11 RS530 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 b ack-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.