8
G.703 CODIRECTIONAL CONVERTER
Data Rate —
64, 56, or 48 kbps, user-selectable
Spare Bandwidth —
[at 56 or 48 kbps:] “1’s” density bit stuffing as per
ITU-TSS V.110; additional asynchronous channel
at 1200 bps; or transfer of RTS to DCD control
signal, end-to-end
Connector —
Models with “-449” affix: DB25 female cabled to
DB37 female;
Models with “-530” affix: DB25 female;
Models with “-V35” affix: 34-pin M-block female;
Models with “-X21” affix: DB15 female
1.3 Data-Communications Control Signals
Functional —
DCD, 64 kbps:
ON when Rx pair contains required
violations, OFF when the Rx pair does not
contain required violations;
DCD, 48 or 56 kbps:
When the Rx pair contains
the required violations, the DCD signal reflects
the state of the remote RTS; DCD is always OFF
when no violations are detected;
CTS output:
ON after RTS ON, with delay; OFF
when RTS OFF, or during Loss of Signal
condition;
DSR output:
ON (+V) when power is available
Clock Source —
From G.703 Receive pair (LBT), from DCE (EXT),
or from internal source (INT), user-selectable;
If LBT, three sub-options are user-selectable:
Unit is DCE and RC and TC signals are outputs
from the unit to the local DTE (LBT-DTE);
RC signal is an output from the unit to the local
DTE, but TC signal is an input from a tail-
circuit DCE (LBT-DCE); or
X.21 only: Unit is DTE and RC and TC signals
are both inputs to the unit from the local DCE
(LBT-DCE21)
