Dataplex DPX-213, User Manual

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APPLICATIONS
Section 5
5-4
Copyright (C) Dataplex Pty Ltd
5.5 Leased Line Operation
The DPX-213 supports leased line operation. This mode (AT&L1) follows the CCITT
recommendations for V.22 and V.22bis and is useful for sync and async applications with
many manufacturers products. The AT&L1 command does not support Constant Speed
Interface or MNP operation. The AT&L1 mode provides a controlled carrier mode based
on the RTS interface lead (AT&K1) which can be made permanent carrier with the AT&D0
command. V.22bis modems have long equalisation and training times (2+ seconds) and are
not suitable for multi-drop operation or fast polling.
This leased line configuration is fully compatible with the CCITT V.22 and V.22bis
recommendations for both synchronous and asynchronous leased line operation. The
modem gains synchronisation on the data stream without requiring a full V.22bis retrain
sequence, making this mode compatible with other V.22bis modems such as the TEL-424.
V.22bis, V.22 and V.21 recommendations are supported in Asynchronous Leased Line
Mode with synchronous operation available at 1200 and 2400 bps. The following set-up
string is provided as a guide (spaces included for clarity):
AT&F F5 &M1 &L1 S0=0 &E &I &W
where
COMMAND DESCRIPTION
AT&F Factory default to define start values.
F5 Force 2400 bps speed.
&M1 Select Synchronous Mode.
&L1 Leased Line mode.
S0=0 Make this end originate.
&E No MNP/V42.
&I No CSI.
&W Write configuration.
The originate end must have S0=0 and the answer end must have S0 set to any value
except zero (typically S0=1 at the answer end). To set the speed of operation enter the
above set-up with the terminal set to 2400 bps. For synchronous operation, use AT&M1 or
AT&M3.
Once on-line, the unit may be returned to Command Mode by issuing an asynchronous
'pause'
+++
'pause' escape sequence. When in Command Mode, the leased line
configuration can be deleted by an AT&F&W or via a Master Rest.