How to Create and Use the Modemlog.txt FileID: Q142730
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This article describes how to create and use a Modemlog.txt file for
troubleshooting modem problems using 32-bit communications programs.
The Modemlog.txt file is created by the Windows communications subsystem
when a TAPI-enabled communications program establishes a communications
session with a modem. Information about the connection is logged
sequentially into the Modemlog.txt file as specific events identified by
date and time.
To enable the creation of the Modemlog.txt file, follow these steps:
<Time/Date> <Message/Status Information>
A program has called TAPI to open this modem's line handle.
Unimodem.tsp called the Win32 function to open a file handle to
Unimodem.vxd for this modem.
Unimodem has called VCOMM to open the correct serial port for this
modem, and set its default COM port settings.
Unimodm sends an 'AT' to initialize the modem's autobaud setting.
The "AT<CR>" is echoed back by the modem, along with an "OK" response
code. Unimodem discards the echoed command, and correctly interprets
the OK response.
Unimodem sends the first initialization string specified in the .inf
file, discards the echoed command, and interprets the OK response
correctly.
Unimodem sends the second initialization string from the .inf file.
The command is echoed back, and numeric response codes are now in use.
Unimodem successfully sends the third initialization string from the
.inf file. Note that this command is not echoed back by the modem.
This is the dynamic initialization stage. Unimodem sent a string to
configure the modem to settings requested by the user or
program. The command string is built dynamically based on registry
keys originally specified by Settings values in the .inf file.
Unimodem first sets dial tone detection on.
Unimodem takes the modem off-hook.
Unimodem dials the phone number provided by the program via TAPI.
Unimodem originates the call. Note that "X3" is included because
this modem will not work correctly without it. Some modems do not
require this.
"Ignore" is misleading. Here, Unimodem recognized "52<CR>" as a call
progress response code.
Unimodem recognized "77<CR>" as a call progress response code.
Unimodem recognized "69<CR>" as indication of a connection.
Unimodem knows that this is a 14,400 bps call with error compression
but no data compression, based on the "52<CR>77<CR>69<CR>" response codes.
The call is now in progress, in use by the program.
Unimodem detected a carrier loss. The call was disconnected by the
other computer. This output is different if Unimodem is called to disconnect.
Unimodem dropped DTR to cause the modem to hang up.
Unimodem.tsp closed its Win32 file handle to the modem.
Additional query words: msn
Keywords : kbtool win95 win98
Version : 95
Platform : WINDOWS
Issue type : kbhowto
Last Reviewed: January 26, 1999