AST RESEARCH, INC. TECHNICAL BULLETIN # 1823 5/26/98
TITLE Microcom 28.8 Travel PCMCIA MODEM will not dial.
ISSUE
On laptop computers the Microcom 28.8 Travel Card Fast MODEM
PCMCIA card will not dial consistently due to an incorrect
registry entry.
When the Microcom MODEM is installed Windows 95 will properly
detect and install the default drivers for it. If diagnostics are
run from the MODEM area of the Device Manager, the Microcom MODEM
will test fine. However, attempting to dial using HyperTerminal
may not work. The MODEM will not dial out using the automatic
dialing mechanism of Win95. However, it will dial out if you
manually type in the AT command used to dial (ATDTxxx-xxxx).
Dial-Up Networking will also experience this same issue. Dial-Up
Networking has no method of manually dialing, therefore you can
not make a connection.
This issue may affect any system with PCMCIA support using any
version of Windows 95.
BACKGROUND
When Windows 95 creates the Registry entry for the Microcom MODEM,
it sets the PortDriver to “ppm.vxd” which is a Parallel Port
driver. Changing the PortDriver to “Serial.vxd”, the generic
Windows 95 serial port driver, corrects the issue.
ACTION
To correct the Registry the PortDriver of the Microcom MODEM must
be modified. Download MICRO-FX.EXE. It will create a 1.44 floppy
disk containing MICROFX1.REG and MICROFX2.REG.
If the Microcom MODEM is the only MODEM in the computer, run the
Registry fix-up file MICROFX1.REG then re-boot the computer.
If the Microcom MODEM is the second MODEM in the computer, run the
Registry fix-up file MICROFX2.REG then re-boot the computer. This
would be the case for computers that have built-in MODEMs like the
Ascentia J or the Ascentia P units.
If the computer has more than two MODEMs it will be necessary to
manually edit the registry entry. MODEM entries are found in the
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\Modem
key. This key is further broken down by the MODEM number.
Example:
In an Ascentia P the built-in MODEM would be # 0000.
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\Modem\0000
The Microcom MODEM would be #0001.
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\Modem\0001
If the Microcom MODEM were the third or fourth MODEM then you
would edit the appropriate key (0003, 0004 etc.)
Once the correct key is found change the PortDriver field from
“ppm.vxd” to “Serial.vxd”. You must then reboot the computer.
NOTES
It is most strongly recommended that you make a backup of the data
on your hard drive before attempting to make Registry
modifications.
You can download this file from the following services:
AST WWW Site: http://www.ari-service.com
AST On-Line! BBS*: See IB0001.TXT
CompuServe: GO: ASTFORUM
Prodigy: JUMP: ASTSUPPORT
* Refer to IB0001.TXT for a list of AST's
international BBS numbers.
SYSTEMS AFFECTED
All AST laptop computers running Windows 95.
TAN 000656PS
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