Eiconcard™ Family Installation Guide
page 33
X.21 interface
A pin-out diagram for the X.21
interface is shown in Figure 11.
The signal definitions and
names are listed in Table 8.
Table 8. X.21 interface signals
Pin #
Signal Name
Direction
CCITT #
1/15
PGND
Protective Ground
Common
101
2
T(A)
Transmit Data (+)
Output
103A
3
C(A)
Control Signal (+)
Output
105A
4
R(A)
Receive Data (+)
Input
104A
5
I(A)
Indication (+)
Input
109A
6
S(A)
Signal Element Timing (+) Input
115A
7
B(A)
Byte Timing (+)
Input
114A
8
SGND
Signal Ground
Common
102
9
T(B)
Transmit Data (-)
Output
103B
10
C(B)
Control Signal (-)
Output
105B
11
R(B)
Receive Data (-)
Input
104B
12
I(B)
Indication (-)
Input
109B
13
S(B)
Signal Element Timing (-)
Input
115B
14
B(B)
Byte Timing (-)
Input
114B
PG N D
1
T(A)
C(A)
R(A)
I(A)
S(A)
B(A)
SGND
T(B)
C(B)
R(B)
I(B)
S(B)
B(B)
PG N D
15
8
9
Figure 11. X.21 interface
64-0308-09.fm Page 33 Monday, March 15, 2010 3:32 PM
