si2439-a-gm Silicon Laboratories, si2439-a-gm Datasheet - Page 44

• Manufacturer Part Number: si2439-a-gm
• Description: V.92 And V.34 Isomodem With Global Daa
• Manufacturer: Silicon Laboratories

Si2494/39
44
Command
%On
%O1
%O2
%Cn
%C0
%C1
%C2
%C3
%Vn
%V0
%V1
%B
%$
Display AT% command settings.
Report blacklist. See also S42 register.
Data compression
Disable V.42bis and MNP5 data compression
Enable V.42bis in transmit and receive paths. If MNP is selected (\N2), then %C1 enables
MNP5 in transmit and receive paths.
Enable V.42bis in transmit path only.
Enable V.42bis in receive path only.
Answer mode.
Si2494/39 will auto-answer a call in answer mode.
Si2494/39 will auto-answer a call in originate mode.
Automatic Line Status Detection.
After the %V1 and %V2 commands are issued, the Si2494/39 will automatically check the telephone
connection for whether or not a line is present. If a line is present, the Si2494/39 will automatically
check if the line is already in use. Finally, the Si2494/39 will check line status both before going off-
hook and again before dialing. %V1 uses the fixed method, and %V2 uses the adaptive method.
%V0 (default) disables this feature.
Disable automatic line-in-use detection.
Automatic Line Status Detection—Fixed Method.
Description: Before going off-hook with the ATD, ATO, or ATA commands, the Si2494/39 compares
the line voltage (via LVCS) to registers NOLN (U83) and LIUS (U84):
Loop Voltage
0  LVCS  NOLN
NOLN  LVCS  LIUS
LIUS  LCVS
Once the call has begun, the off-hook intrusion algorithm (described in "4.16.2. Off-Hook Intrusion
Detection" on page 23) operates normally. In addition, the Si2494/39 will report “NO LINE” if the tele-
phone line is completely disconnected. If the HOI bit (U77, bit 11) is set, “LINE IN USE” is reported
upon intrusion.
Table 12. Extended AT% Command Set (Command Defaults in Bold)
Action
Report “NO LINE” and remain on-hook.
Report “LINE IN USE” and remain on-hook.
Go off-hook and establish a modem connection.
Rev. 1.0
Action