Link Interfaces Reference
IOLINK-PRO & 520 Reference Manual —

3.11

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
Test Mo de
ClearTo Send (A)
DB25MALE
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
DB25MALE
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)
Request ToSend (A)
Request ToSend (B)
ReceivedLine S ignal Detector(A)
ReceivedLine S ignal Detector(B)
DTEReady (A)
DTEReady (B)
Signal Ground
TransmitTiming (A) DTE Source
TransmitTiming (B) DTE Source
Local Loopback
RemoteLoopback
Receiver Timing(A) DCE Source
TransmitTiming (A) DCE Source
TransmitTiming (B) DCE Source
TestMode
Shield
Receiver Timing(B) DCE Source

Figure 3 – 13 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 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.