Specifications

AN93
42 Rev. 0.9
3.1.9. Extended AT Commands
The extended AT commands, described in Tables 19–21, are supported by the Si2493/57/34/15/04.
Table 19. Extended AT& Command Set
Command Action
&$ Display AT& current settings (see text for details).
&Dn Escape Pin Function (Similar to DTR)
&D0 ESC (pin 22) is not used
&D1 ESC (pin 22) escapes to command mode from data mode if also enabled by HES U70, bit 15.
&D2 ESC (pin 22) assertion during a modem connection causes the modem to go on-hook and return to
command mode.
&D3 ESC (pin 22) assertion causes ATZ command (reset and return OK result code).
&Gn Line connection rate limit—This command sets an upper limit on the line speed that the
Si2493/57/34/15/04 can connect. Note that the &Hn commands may limit the line speed as well
(&Gn not used for &H0 or &H1). Not all modulations support rates given by &G. Improper settings
are ignored.
&G3 1200 bps max
&G4 2400 bps max
&G5 4.8 kbps max.
&G6 7.2 kbps max.
&G7 9.6 kbps max.
&G8 12 kbps max.
&G9 14.4 kbps max (default for Si2415).
&G10 16.8 kbps max.
&G11 19.2 kbps max.
&G12 21.6 kbps max.
&G13 24 kbps max.
&G14 26.4 kbps max.
&G15 28.8 kbps max.
&G16 31.2 kbps max.
&G17 33.6 kbps max (default for Si2457 transmit and Si2434).
&Hn Switched network handshake mode—&Hn commands must be on a separate command line from
ATD, ATA, or ATO commands.
&H0 V.90 with automatic fallback (56 kbps to 300 bps) (default for Si2457).
&H1 V.90 only (56 kbps to 28 kbps).
Notes:
1. The initial number attempted to test for an outside line is controlled by S51 (default = 1).
2. AT&$ reflects the last AT&P command issued but does not reflect any subsequent changes made by writing U-registers
with AT:U.