User's Guide

The Operational View SB300 Series
Page 66 Proprietary and Confidential 2110059 Rev 1.1
-K0 This is a companion to the above command indicating a preference for LAPM
when using V.42.
*H0 This sets the Link Negotiation Speed for the initial connection to a maximum
equivalent to the DTE speed. It will adapt to the speed of the other modem.
S7=120 The Wait for Carrier is set higher than the default 50 seconds to allow for the
added time of cellular (and possibly modem pool) connections. This sets the
wait to 120 seconds.
S10=100 Lost Carrier Hang-up Delay is set to 10 seconds. The default is 0.6 seconds but
cellular links can be interrupted during cell changes and due to other “noise” so
the modem will wait longer to determine if the connection is truly lost.
S51=15 This sets the V.34 symbol rate to 2800 symbols per second and the carrier
frequency control to automatic for transmissions. The default would allow 3429
symbols per second, which is likely to lead to more failures and retransmissions.
S52=15 This does the same as S51 but for the V.34 receive side.
S55=37 V.34 options are set to enable asymmetric bit rates, and non-linear encoding. It
disables asymmetric rates, constellation expansion and receiver pre-encoding.
S70=20 This extends the maximum number of retransmissions from the default 12 up to
20. Higher values are possible if needed.
S96=29 ETC Options are set to enable all features for ETC handshaking except cellular
network compensations are not enabled since your end is non-cellular. This
includes enabling a fallback to 1200 bps if higher rates cannot be supported. It
also enables /ETC to be appended to the CONNECT message.
S106=32 The frame size for error correction protocols is set to the minimum 32. The
default is the maximum of 128. Use of a small frame size does reduce direct
throughput, but gives a more robust connection. This leads to fewer
retransmissions and can improve overall throughput in noisy connections that
require frequent retransmissions.
The data rate discussion in Section 6.5.1.1 also applies to this type of connection.
7.3. Originate a Wireline Connection
Watcher (Section 0) can be used to set the modem to Wireline operation. When set, a call can be
placed using any modem application which can issue a dial command to the COM port.
Alternatively, Windows Dial-up Networking can be configured to establish a connection. If Dial-
up Networking (or any other communication application) is used to setup the modem, the setup
string should be:
AT &F0 for calls to a wireline modem destination
– OR –
AT &F6 for calls to a cellular modem destination
You may freely add necessary settings to control the local DTE/DCE interface (echo, verbose,
quiet, etc.) without altering the remote connection settings.