Silicon Laboratories Si2404, Manual, Page: 63 / 307

AN93
Rev. 1.4 63
The modem has a 48-character buffer, which makes it possible to enter multiple AT commands on a single line.
The multiple commands can be separated with spaces or linefeed characters to improve readability. AT, space and
linefeed characters are not loaded into the buffer and are not included in the 48-character count. The command
line must end with carriage return for the modem to begin executing it. The modem ignores command lines longer
than 48 characters and reports ERROR. Table 47 shows examples of multiple AT commands on a single line.
When concatenating commands on the same line, the following must also be taken in to account:
 A semicolon is used to append to :U or :R commands. For example, AT:U42,0022;:R43;S6=4.
 The cIPR cannot be on the same line as a :U or :R command.
 The commands *Y, :W, :P, +MS and +MR cannot be appended to. They must be the last command in a string.
 The command AT+GCI=9 must be on a line of its own.
 Consecutive U registers can be written in a single command as AT:Uhh,xxxx,yyyy,zzzz where hh is the first U-
register address in the three register consecutive series. This command writes a value of xxxx to Uhh, yyyy to
Uhh+1, and zzzz to Uhh+2. Additional consecutive values may be written up to the 48 character limit.
Table 46. Command Examples
Command Result Comment
AT$ E = 001 Configuration status of basic
AT commands.
M = 000
Q = 000
V = 001
X = 004
Y = 000
AT&$ &D = 001
&G = 017
Configuration of &AT
commands.
&H = 000
(Si2457)
&P = 000
ATS2? 043 S-register 2 value—Escape
code character (+).
AT:R2C 00A0 Value stored in register U2C.
Table 47. Multiple AT Commands on a Single Line
Command Result
ATS0=4M1X1<CR> The modem auto-answers on the
fourth ring. The speaker is on during
dial and handshake only. Blind dial-
ing is enabled.
AT S0=4 M1 X1 <CR> Same as above (spaces do not mat-
ter).
ATS0=4<CR> Same as above.
ATM1<CR>
ATX1<CR>