Modem filter driver

Hi All,
I’d like to provide traffic monitoring on PCMCIA modem that is 16450/550
UART compatible and appears as a new COM port when plugged in.
In other words I’d like to switch the modem off if it is idle for some
period of time.
So, I thought of creating a filter driver that will be loaded as an upper
filter on Serial.sys. This way my filter driver will see all packets sent to
my modem device.

Question: What registry setting do I need to change to load my driver as an
upper filter to Serial.sys ?
Can I load my filter driver dynamically on the modem plugin ?
I need some universal approach that will work for 95,98, NT4, 2k.
Ideas, opinions please.

Stas.


You are currently subscribed to ntdev as: $subst(‘Recip.EmailAddr’)
To unsubscribe send a blank email to leave-ntdev-$subst(‘Recip.MemberIDChar’)@lists.osr.com

>I’d like to provide traffic monitoring on PCMCIA modem that is 16450/550

UART compatible and appears as a new COM port when plugged in.
So, I thought of creating a filter driver that will be loaded as an upper
filter on Serial.sys. This way my filter driver will see all packets sent to
my modem device.

Under NT4, this is a fine approach (note though that the serial devices can
vary in terms of their exact names, but you can always retrieve the name of
the serial device for a given COM port from the registry).

However, under Win2000, the serenum.sys driver sends packets directly into
serial.sys, explicitly bypassing any filter drivers which were added after
serenum.sys was loaded (see the source for the serenum driver in the
Win2000 DDK). If you attach a filter driver to the serial device, you’ll
see only the occasional requests which do not originate from serenum.sys.

Instead, try installing a class filter for the whole modem class. (Peter
Viscarola once showed me some sample code regarding how to write a class
filter. Peter, would you care to elaborate here?)

  • Avi

You are currently subscribed to ntdev as: $subst(‘Recip.EmailAddr’)
To unsubscribe send a blank email to leave-ntdev-$subst(‘Recip.MemberIDChar’)@lists.osr.com