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Vectra VL400 DOS incompatibility ???

BRAHIM KHOUDIR
Occasional Contributor

Vectra VL400 DOS incompatibility ???

i'm using a Vectra VL400 under WIN98:
I've a DOS application that use an external modem that works fine under True Dos mode, but the modem hungs if this DOS program is executed from WIN98
The DOS program run correctly under other older PC
It also runs under Failsafe Mode
So I've suspected a windows driver that
cause this problem
The soulution i found for this DOS program to run under win98 is:
For the Registy Key: for Modem on COM1 \HKEY_LOCAL_MACHINE\System\CurrentControlset\Services\Class\Ports\0000
Devloader ="" instead of "*VCOMM"
so i suppose that VCOMM ( plug & play Driver for com port ) is responsible of that problem, but I've no more access to my modem under Windows
Is it an incompatibility issue of the VL400 ?

Thanks for help
2 REPLIES
Dries Bertier
Respected Contributor

Re: Vectra VL400 DOS incompatibility ???

I noticed the same problem under WIN98. It seems like there is a sort of incompatiblity between the vectra and windows 98 modem support. I configured my system to use the modem in 'windows' dos by using a reservation for the IRQ of the communication port.(control panel - system - device manager - double click on computername). By using the reservation the computer will not assign the communication port (fe COM1) to the modem because it is reserved. In that way it is possible to use the port in dos (it is free); so you can use the modem in dos. This is only a workaround, when you need the modem in windows you have to remove the reservation and reboot for proper configuration. It is also possible to use serveral hardware profiles to fix the problem but i haven't found a solution yet to use the modem both in dos and windows. True dos works fine because there is no windows driver that takes a communication port, all ports are free to use. When WIN98 is loaded, and the device driver for the modem is loaded, the communication port for the modem is assigned and left open during the entire session. When the port is open, no other device can use it...
<< please try >>
K.Garrett
Regular Advisor

Re: Vectra VL400 DOS incompatibility ???

Hi Brahim
I would advise you to try the registry hack clearly documented as Article ID: Q252184
on the Microsoft Knowledge Base