Black Box LR5100A-T - Manual (Page 94)

Interface Pinouts
86
RS232 Null-Modem Cable Configuration
Figure D-9 RS232 Null-Modem Cable
The connecting cable must be a shielded 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.
Shield
Signal Ground
DB25 MALE
1
20
7
8
15
17
24
DB25 MALE
1
8
7
20
24
17
15
Signal Ground
Shield
Transmitted Data Received Data
Received Data Transmitted Data
Request To Send
Request To Send
Received Line Signal Detector (CD)
Data Set Ready
Data Set Ready
Received Line Signal Detector (CD) DTE Ready
DTE Ready
Transmit Timing DCE Source
Receiver Timing DCE Source
Transmit Timing DTE Source
Receiver Timing DCE Source
Transmit Timing DCE Source
Transmit Timing DTE Source
2 3
2 3
4 6
4 6