Serial port
127
Models 2603, 2621, and 2635 Getting Started Guide
D • IPLink Physical Connectors
X.21 (DB-15 Connector)
The X.21 interface in the Model 2621 may be configured for either DTE or DCE. Default is DCE.
Figure 85. X.21 DB-15 connector
Table 10. X.21 Interface (Model 2621)
Pin No. Circuit
Signal Name
Direction
1
G
Signal Ground or Common
Return
-
2
T
Transmit (Data)-a
from DTE
3
C
Control-a
from DTE
4
R
Receive (Data)-a
to DTE
5
I
Indication-a
to DTE
6
S
Signal Timing-a
to DTE
7
-
-
-
8
Ga
DTE Common Return
-
9
T
Transmit (Data)-a
from DTE
10
C
Control-b
from DTE
11
R
Receive (Data)-b
to DTE
12
I
Indication-b
to DTE
13
S
Signal Timing-b
to DTE
14, 15
-
-
-
1 Frame Ground
2 Transmit – A
3 Control – A
4 Receive – A
5 Indication – A
6 Signal Timing – A
7
8 Signal Ground
9
10
11
12
13
14
15
Transmit – B
Control – B
Receive – B
Indication – B
Signal Timng – B
