Table of Contents
Advertisement
Installation
Table 2-1. Digital Interface Signal Descriptions (Continued)
Pin
EIA-
CCITT
No.
232D
V.24
9
10
11
15
DB
17
DD
18
20
CD
108.2
21
22
CE
23
CH
* Modem options may force these signals on or cause them to be ignored.
† This function can be disabled or its logic sense reversed by hardware straps.
Refer to Strap Options.
2-4
Signal
Name
+12 Volts
-12 Volts
Signal Qual-
ity
Indicator
114
Transmit
Clock
(DCE)
115
Receive
Clock
141
Local Loop-
back
(Loop 3)
Control
Data Termi-
nal Ready
140
Remote Dig-
ital
Loopback
125
Ring Indica-
tor
111
Data Rate
Select
Description
+12 voltage reference
-12 voltage reference
This circuit indicates probability of errors
in the received data: a positive level indi-
cates poor signal quality while a negative
level indicates good signal quality. †
A transmit data rate clock output for use by
an external data source: Positive clock
transitions correspond to data transitions.
A receive data rate clock output for use by
an external data sink: Positive clock transi-
tions correspond to data transitions.
A positive level causes the modem to enter
the local analog loopback test mode.*
This circuit is positive when the DTE is
ready to originate or answer a call in dial-
up operation. DTR must always be active
(high) in 2-wire private line operation.
Cycling DTR causes retraining.*
A positive level causes a digital loopback
test mode at the remote modem.*
In direct dial operation this circuit is posi-
tive in response to an incoming ring sig-
nal.*
Supplies a data rate control input to select
primary or fallback data rate: Negative
voltage selects primary data rate and posi-
tive voltage selects fallback data rate.*
V.3400
Advertisement
Table of Contents
