Link Interfaces Reference
3-2 — Orbitor 3000 Reference Manual
When connecting two bridge/routers back-to-back with CSU/DSU link modules, a null-modem cable is required to
crossover the pins on the links. Crossing over the pins allows two bridge/routers both configured as DTE interfaces to be
connected together.
A DSU/CSU crossover cable would be constructed as follows:
1 --> 7
2 --> 8
7 --> 1
8 --> 2
Console Pinouts
The connector shown here and pinouts described here correspond to
the connector labeled “Console” on the back of the Orbitor 3000.
13
1
25
14
DB25 Female DCE
Contact
Number
CCITT
Circuit
Number
Circuit
Circuit
Name
Direction
To From
DCE DCE
1
101
AA
Protective Ground
NA
2
103
BA
Transmitted Data
X
3
104
BB
Received Data
X
5
106
CB
Clear to Send
X
6
107
CC
Data Set Ready
X
7
102
AB
Signal Ground
NA
8
109
CF
Received Line Signal Detector (CD)
X
20
108.2
CD
Data Terminal Ready
X
22
125
CE
Ring Indicator
X
Figure 3—2 Console Pinouts
The connecting cable must be a shielded cable.
When connecting the Orbitor console directly to a modem, a null modem cable must be used because both the Orbitor
console and the modem are DCE devices. A null modem cable with pinouts according to the following figure must be
used.
Orbitor Contact
Number
Modem Contact
Number
8
20
3
2
2
3
20
8
7
7
4
5
5
4
22
22
Figure 3—3 Console Null Modem Cable Pinouts
