0049-2702-XXX Alliance Series Modems – USER MANUAL
08/05/2010
Rev. A
Page 17 of 197
If the connection is a V.32bis connection, the ALX will default to V.13 mode (with the V.13
Operation option set to the TX AND RX selection).
The ALX will not handshake in V.22bis,
V.21/V.22/V.23 or Bell 212/103 mode when it is configured for V.3x/208 auto-detect mode.
For additional information on Bell 208 operation, see Chapters 2 (
Communication Standard
section) and 3 (section titled
Dumb Mode and Bell 208 Operation
).
4-Wire Leased Line V.29 Mode
V.29/V.27/V.26 capabilities
are optional on certain models (as listed in Table 1-2). All features,
options or information in this manual identified as V.29-, V.27-, V.26- related apply only to
models that include the V.29/V.27/V.26 option. If you are not sure if your modem includes the
V.29/V.27/V.26 option, check the Quick Setup menu on the front panel LCD. Quick Setups 13
through 16 (for V.29 and V.27) are present only on models that include the V.29/V.27/V.26
option.
The following information applies to 4-wire leased line V.29 operation:
•
The modem must be configured for use with a 4-wire line.
If you have selected the 4-Wire Leased Line V.29 Quick Setup, the line type will be set
automatically to the correct setting.
•
Operation is restricted to data rates of 4800, 7200 and 9600 bps.
•
Lines can be conditioned or unconditioned.
After you select the 4-Wire Leased Line V.29 Quick Setup, the ALX will send a training
sequence and wait for a training response from the remote modem. The ALX will repeat the
training sequence every 1.2 seconds until the remote modem responds.
When the local modem has established a connection with the remote unit, the TIA/EIA status
screen will be present. Typically this screen will look like this:
Note:
For point-to-point 4-wire leased line V.29 operation, the Auto-Retrain option should be
enabled on both modems. (Auto-Retrain is enabled by default if you select the 4-Wire Leased
Line V.29 Quick Setup.) If the Auto-Retrain option is disabled, the modem will not transmit a
training sequence and will instead train on the data stream from the remote modem. Disabling
Auto-Retrain in 4-wire leased line V.29 mode is recommended for test purposes only. If Auto-
Retrain is disabled, it should be disabled on both modems.