Specifications

Si2404
26 Rev. 0.91
Extended AT Commands
The extended AT commands are supported by the Si2404 and are described in Tables 10 through 12.
Table 10. Extended AT& Command Set (Command Defaults in Bold)
Command Action
&$
Display AT& current settings.
&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).
&F
Restore factory default settings.
&Gn
Line connection rate limit—This command sets an upper limit on the line speed that the Si2404 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. Any improper setting will be ignored.
&G3
1200 bps max
&G4
2400 bps max
&Hn
Switched network handshake mode—&Hn commands must be on a separate command line from
ATD, ATA, or ATO commands.
&H6
ITU-T V.22bis only (2400 bps or 1200 bps)
&H7
ITU-T V.22 only (1200 bps)
&H8
Bell 212 only (1200 bps)
&H9
Bell 103 only (300 bps)
&H10
ITU-T V.21 only (300 bps)
&H11
V.23 (1200/75 bps)
&Pn
Japan pulse dialing
&P0
Configure Si2404 for 10 pulse-per-second pulse dialing. For Japan.
&P1
Configure Si2404 for 20 pulse-per-second pulse dialing. For Japan.
&Tn
Test mode
&T0 Cancel test mode (Escape to command mode to issue AT&T0). This command will also report the
number of bit errors encountered on the previous &T4 or &T5 test.
&T2
Initiate ITU-T V.54 (ANALOOP) test. Modulation set by &H AT command. Test loop is through the
DSP (Si2404 device) only. ISOmodem® echoes data from TX pin (Register 0 in parallel mode) back
to RX pin (Register 0 in parallel mode).
&T3
Initiate ITU-T V.54 (ANALOOP) test. Modulation set by &H AT command. Test loop is through the
DSP (Si2404), DAA interface section (Si2404), DAA interface (Si3010), and analog hybrid circuit
(Si3010). ISOmodem echoes data from TX pin (Register 0 in parallel mode) back to RX pin (Regis-
ter 0 in parallel mode). Phone line termination required as in
Figure 1. To test only the link operation,
the hybrid and AFE codec can be removed from the test loop by setting the DL bit (U62, bit 1).