Ositech comm Trumpcard Data/Fax Modem - Manual (Page 34)

4 - 2 Trumpcard 14400/28800 Modem
Section Four
Modem Command Guidelines
Each of the following modem command descriptions has a list of
possible parameters with their default values. The modem loads the
default values at initialization (when you turn the power on or you issue
the ATZ command). If you exclude a mandatory parameter, the modem
assumes a zero value. Invalid commands or parameters return the
ERROR message.
The command line may contain a single command or a series of
commands. You can separate commands with a space for readability,
but, the command line can not exceed 41 characters. The modem
performs the command after you send a terminating character. The
default terminator is carriage return (ASCII 013), but you can change this
by writing to register S3.
You can edit the command line using the backspace character (ASCII
008); change this by writing to register S5. However, the backspace can
not be 0, greater than 127, or the terminating character.
All command lines begin with AT (in capital or lower case letters). A
command line can be terminated at any time by issuing CTRL-X (ASCII
018). The modem will ignore the command line and return an OK
message. You can use A/ to repeat the last command line. The A/ does
not require a terminating character.
An escape code sequence (+++) returns the modem to the command
mode from the data mode. There must be a time delay between the last
character transmitted and the first character of the escape code. You can
change the delay by writing to register S12; (default 1 second). The
escape code character must occur three times in succession for an
escape.
Parameters that are entered for the AT and the AT& commands are
limited in value to 0-255, where the parameter is "MOD"ed with 256. The
result must be within the specified range; if it is not, the modem returns
an ERROR message.
Parameters entered for an S register are also "MOD"ed with 256.
Parameters that are out of range are stored in the S register, however, no
ERROR message is reported. Functionally the lower or higher register
limit is used.