User's Guide

User’s Guide Modem Basics
2110059 Rev 1.1 Proprietary and Confidential Page 23
• Quiet result codes disabled (Q0): which enables the modem to issue result codes following
commands.
• Verbose result codes (V1): which provides results in English text appended with <CR><LF>.
• SB320 Speaker Control is set to be on until carrier detected (M1).
This setting means that a host running a terminal emulation program for communication with the
modem should have this configuration:
• Emulation – TTY
• ASCII character
Sending:
• No line ends with line feeds
• No local character echo
Receiving:
• Do not append line feeds to incoming line ends
• Do not force incoming data to 7-bit.
• Wrap lines if necessary
Commands may be entered in upper or lower case.
4.3.3. DTR Signal Handling
The modem can be configured to handle the DTR signal from the host in several ways. The AT
command &D sets the method. The factory default is to hang up any remote connection and enter
command state with auto-answer disabled (&D2).
If you experience difficulty entering command state from a data state you may wish to have the
modem reset on DTR transition.
The available options are:
&D0 Ignore DTR
&D1 Enter command state without changing on/off-line condition.
&D2 Hang up (close active session) and enter command state with auto-answer disabled.
&D3 Reset immediately (no reply is issued). (This is available on the SB320 only and not in
CDPD mode.)
4.3.4. DSR Signal Control
The SB300 Series modems will leave the DSR signal active whenever the modem is powered on.
There is no control of this signal. This signal is not an indication that the modem is ready for use.
CTS is activated when the modem has completed its internal initialization and is ready.
4.3.5. Local Flow Control
The modems currently handle only hardware flow control (RTS/CTS). This is the factory default
as well. The SB320 in non-CDPD modes also supports the &K command to adjust this in future
firmware revisions. The options are:
&K0 Disable local flow control
&K3 Use RTS/CTS hardware control
&K4 Use XON/OFF software flow control. Don’t use this if these characters can be part of the
data stream.
There is also an impact to flow control with the use of the Communication Mode command (&Q)
available on the SB320 in non-CDPD modes. This command effects the use of internal data
buffering at the modem. If buffering is disabled, so is flow control.