STAT-4, STAT-8, AND STAT-24
50
Table A-1 (continued). Main (composite) channel connector.
CCITT V.24
EIA RS-232C
Pin
Signal
Description
Circuit Number Line
Name
108
CD
20
Data Terminal Ready
Continuous positive level from
stat mux
140
—
21
Loop 3 Test Command
Control signal from stat mux to
modem. Positive level commands
attached modem to send a remote
loopback command to the remote
modem.
If the attached modem uses pin 21
as a signal quality indication output,
set pin 21 to OFF, thereby disabling
this function—refer to
Section 3.3
.
A.2 Sub-Channel Interface
Stat mux sub-channel interfaces are configured as synchronous DCE RS-232 interfaces. The sub-channel
connectors have RJ-45 sockets. Table A-2 lists pin allocations.
Table A-2. Sub-channel connectors.
CCITT V.24 EIA RS-232C
RJ-45
Signal
Description
Circuit
Line
Pin
Name
101
AA
1
Protective Ground
Chassis ground (may be isolated
from signal ground or connected
to it—refer to
Section 3.3
)
102
AB
7
Signal Ground
Common signal and DC power
supply ground
103
BA
5
Transmit Data
Serial digital transmit data from
a terminal or other source
104
BB
3
Receive Data
Receive data provided by
stat mux receiver
105
CA
2
Request to Send
Continuous positive level received
by the stat mux from DTE, controls
DCD at remote side
