Serial port
124
Models 2603, 2621, and 2635 User Manual
D
• OnSite Physical Connectors
Table 9. V.35 pin-out for M/34 & DB-25 connectors
M/34
Pin No.
DB-25
Pin No.
Signal Name
Direction
A
1
Frame/Chassis
Ground
n/a
P
2
TD-a
from DTE
R
3
RD-a
to DTE
C
4
RTS
from DTE
D
5
CTS
to DTE
E
6
DSR
to DTE
B
7
Signal Ground
n/a
F
8
CD
to DTE
X
9
RC-b
to DTE
10
W
11
XTC-b
from DTE
AA
12
TC-b
to DTE
13
S
14
TD-b
from DTE
Y
15
TC-a
to DTE
T
16
RD-b
to DTE
V
17
RC-a
to DTE
L
18
Local Loopback
to DTE
19
H
20
DTR
from DTE
N
21
Remote Loopback to DTE
22
23
U
24
XTC-a
from DTE
M
25
Test Mode
to DTE
X.21 (DB-15 Connector)
The X.21 interface in the Model 2621 may be configured for either DTE or DCE. Default is DCE.
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
