28
MINI-MODEM V.92
4.5 V.92 Operation
Because the V.92 protocol is relatively new and still largely unsupported by central
servers, some features are disabled by default in the initial release of the Mini-
Modem V.92. This section describes the status of the V.92 features in the initial
release. Please note that the V.92 special features require connection to a V.92-
capable server.
• General. The V.92 protocol is enabled by default. If the Mini-Modem V.92
detects another V.92 modem during the handshake phase, they will connect in
V.92 mode; otherwise, they will connect in V.90 mode or the highest mutually
acceptable mode. The AT command that controls this is +MS=.
• Commands. AT commands specific to the V.92 protocol and the new V.44
compression protocol begin with the plus character (+). These commands are
described beginning in Chapter 5. Also, the S109 register has been modified to
support V.92.
• PCM Upstream. This is disabled by default. To upload files at speeds above
33.6 kbps, you must enable PCM Upstream using the command +PIG=1.
Please note that this requires connection to a V.92-capable server. Also, please
note that since upload speeds are affected by line conditions, meeting the
previous requirements cannot guarantee speeds above 33.6 kbps.
• Quick Connect. This shortens the handshake time with another V.92 modem
and is disabled by default. To enable Quick Connect, use the command
+PQC=0
. Quick Connect speeds connect times by skipping the line test during
the handshake and using the configuration from the last data connection.
Therefore, Quick Connect works best when line conditions are consistent from
call to call. If line conditions are variable, enabling Quick Connect can actually
increase the connect time slightly.
• Modem on Hold. With this function, you can put a V.92-capable server on
hold while you take another call (see Chapter 8). Modem on Hold operation
is possible only with the MTMoh Modem on Hold program included with
the Mini-Modem V.92. MTMoh is initially supported only on Windows 95, 98,
and Me. However, Windows NT, 2000, and XP support is expected soon, and
may be available by the time you receive your modem (for details, please call
Black Box Tech Support).
NOTE
For firmware updates for the Mini-Modem V.92, call Black Box Technical
Support at 724-746-5500.