ABB 1MRS119000 Operator's Manual page 15

3.0
3.1
3.2
3.2.1
3.2.2
3.2.3
3.3
3.3.1
3.3.2
Command overview
Introduction
AT commands are the means by which the modem is configured. The available commands
enable reading and modifying of the modem parameters. This chapter describes the AT
commands recognized by the 1MRS119000 modem board. The sections of this chapter
describe the command syntax and give a detailed description of the available AT com-
mands and S registers. For a brief description of the commands refer to appendices.
Command syntax
DTE Commands
The ISO 646 character set (CCITT T.50 International Alphabet 5, American Standard
Code for Information Interchange) is used for issuing commands and responses. Only the
low-order 7 bits of each character are used for commands or parameters; the high-order bit
is ignored. Upper-case characters are equivalent to lower-case characters.
AT command guidelines
Modem operation is controlled by generic AT commands. These AT commands may be
basic AT (i.e., commands preceded by AT, AT&, AT%, AT*, AT\, AT), AT, or AT#), S
register (e.g., S6=n), commands. The command syntax and operation guidelines govern-
ing each of these command categories are described in the subsequent sections.
Basic command syntax
Characters within the command line are parsed as commands with associated parameter
values. The basic commands consist of single ASCII characters, or single characters pre-
ceded by a prefix character, followed by a decimal parameter (e.g., `&D1`). Missing deci-
mal parameters are evaluated as 0.
AT command
AT command guidelines
The basic AT commands used to control modem operation are defined in this section.
These commands are summarised in Appendix A. All these commands may not be avail-
able in a specific product depending upon supported data rates and modes. The default
values are typical of a fully configured modem supporting all data rates and options. The
actual default value is dependent upon modem firmware as defined by the firmware release
notes.
AT Commands, DTE Adaptation
Under AT operation, the serial interfaced modem performs an autobaud/autoparity/
autolength function on each AT header entered. The autolength/autoparity facility can
detect 7- or 8-bit characters of even, odd, or no parity with one stop bit.
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