The X.21 Interface - IBM PCI WAN 2 Port S91 Installation Manual

The X.21 Interface

The pin-out assignments for the X.21 interface
are shown in the following diagram.
The signal definitions and names are listed in
Table 9 below.
Pin # Signal
1/15 PGND
2 T(A)
3 C(A)
4 R(A)
5 I(A)
6 S(A)
7 B(A)
8 SGND
9 T(B)
10 C(B)
11 R(B)
12 I(B)
13 S(B)
14 B(B)
VHSI—X.21 Connections
The wiring diagram below shows the connections required to construct a
VHSI—X.21 cable. For the additional information required to construct your
own cables, see "VHSI Cable Construction Information" on page 10.
VHSI
1
19
4
22
5
23
6
24
8
26
11
29
12
30
Name
Protective Ground
Transmit Data (+)
Control Signal (+)
Receive Data (+)
Indication (+)
Signal Element Timing (+)
Byte Timing (+)
Signal Ground
Transmit Data (-)
Control Signal (-)
Receive Data (-)
Indication (-)
Signal Element Timing (-)
Byte Timing (-)
Table 9: X.21 Interface Signals
TWISTED PAIRS
(MANDATORY)
DRAIN WIRE
BRAID
Figure 15: VHSI—X.21 Connections
PG N D
T(A)
C(A)
R(A)
I(A)
S(A)
B(A)
SGND
Figure 14: X.21 Interface
Direction
Common
Output
Output
Input
Input
Input
Input
Common
Output
Output
Input
Input
Input
Input
19 VHSI Port Interface Specifications
1
9
T(B)
C(B)
R(B)
I(B)
S(B)
B(B)
PG ND
15
8
CCITT #
101
103A
105A
104A
109A
115A
114A
102
103B
105B
104B
109B
115B
114B
X.21
8
2
9
7
14
4
11
6
13
5
12
3
10
1