Switching baud rates on notebooks

[dsc]

Hello,
I have an application where I need to change the serial port baud rate
on the fly. I am using Tcl.

What I am doing is changing the baud rate at the remote computer, then
I close the serial port on my end and re-open it with a different baud
rate. This works fine on my desktop work station. The only issue I have
had doing this is that the notebook computer, that I some times use,
which is a Dell Notebook L400, requires the remote computer to wait
about 2 seconds before sending data at the new baud rate.

My questions is: does anyone know how long it takes for the serial
ports on Notebooks to re-configure themselves?

I need to know this because if this is a hardware dependent issue I
need to allow for the worst case time at the remote computer such it
will work with any computer.

Dave

 

[Guest]

If the PCs use modems, these can be set to communicate using an internal,
error correcting protocol which can be set to autonegotiate baud rates.
Then, you set both PCs to run at rates that are higher than the modem rates,
e.g., 115K, and the modems take care of feeding the data to the app. That's
assuming there are modems involved here.

If no modems are involved, then I don't think that the serial port actually
can detect any baud rate change. You may have in this mix the Windows
telephony driver, rather than just a straight serial link. Look for
Telephony in Computer Managment/Services. If so, you could stop it to get
the apps to talk directly to each other. Then, data rate changes can be
controlled by the apps themselves.

What is the serial port commo for? How does tcl figure into this?