User guide

ADVANCED COMMUNICATIONS WORKING WITH MODEMS
REVISION 1 PAGE 39
• No Flow Control
• Modem must ignore RTS
• DSR override, always on
• Auto answer disabled
• Escape character set to 43 decimal
• 500 millisecond guard time for the escape code sequence (+++)
The following sequence shows the init strings send to modems:
AT COMMAND STRING DESCRIPTION
AT&FE0 &F - set factory defaults (same as &F0)
E0 - disable echo
ATH0Q0V1 H0 - Hang Up
Q0 - Displays result codes
V1 - Verbal codes
ATL1M1X3 L1 - Low speaker volume
M1 - Speaker on until connect
X3 - Sets result codes
AT&C1&D0&H0&I0&R1&S0 &C1 - Normal CD operations
&D0 - DTR override
&H0 - Flow control disabled
&I0 - software flow control disabled
&R1 - Modem ignores RTS
&S0 - DSR override; always on
This string can be modified within C2
ATS0=0S2=43S12=25 S0=0 - auto-answer disabled
S2=43 - set Escape Character to 43 decimal
S12=25 - Sets the duration, in fiftieths of a second, of
the guard time for the escape code sequence (+++)
TROUBLESHOOTING MODEM COMMUNICATION
The PPP and Modem Client and PPP and Modem Server protocols provide a Log File
property to log communication exchange with the modem to a file on the CompactFlash card.
This file is used for debugging purpose during initial modem setup. Be sure to disable this
feature once the correct modem configuration sequence has been established.