Black Box ME444AE-R3 Manual De Usuario
32
256-KBPS LINE DRIVER (V.35, RS-530, OR X.21)
Table 4-5. Pinout of the RackNest 2/14’s DB25 connector when
ME445C-X21 is installed.
SIGNAL
ITU-TSS
LEAD
DB25
DA15
NAME (ABBREV.)
CIRCUIT
TYPE (RACK-
(NORM.
NEST)
X.21)
PIN*
PIN
Shield (n/a)
101
1
1
Ground (G)
102
7
8
a.k.a. Signal Ground (SGND)
Transmit (T)
103
A
2
2
B
14
9
Receive (R)
104
A
3
4
B
16
11
Control (C)
105
A
4
3
a.k.a. Request to Send (RTS)
B
19
10
Indication (I)
109
A
8
5
a.k.a. Carrier Detect (CD)
10
12
RS-530: Transmitter Signal Element
113
A
24
7†
Timing (DTE Source) (TSETT)†
B
11
14†
Signal Timing (S)
114
A
15
6
B
12
13
*This pinout follows the TIA RS-530 standard.
†Standard X.21 does not support an external clock, and specifies that DA15 Pins 7
and 14 should be used for the Byte Timing (B) A and B signals. Because Byte
Timing is hardly ever used, but an external clock is often necessary for today’s
data communication, many Black Box devices are designed to this modified
specification in which the RS-530 external-clock signal replaces Byte Timing.
Timing is hardly ever used, but an external clock is often necessary for today’s
data communication, many Black Box devices are designed to this modified
specification in which the RS-530 external-clock signal replaces Byte Timing.