Both cards want to use com 1

[DragnLady]

We use CDPD modems and have a data acquisition cards that both default to com1.
We are using manual DB9 switches, which is working fine.
But what I was wondering was if a Serial DB9 'Y' splitter could do the same job as a Manual DB9 switch? It would take up much less space...
Or would both cards most likely be trying to access com1 at the same time?

 

[edfair]

Depends on your operating system and the application program.
Anything later than windows3 will probably need to stay on the switch. But maybe on a A/B switch. As I read your post you indicate multiple switches, which may be overkill.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[DragnLady]

Sorry. multiple switches as in multiple systems.
Only one switch per system.
OS is actually Linux. systems run on a version of the Knoppix CD.
I am just not sure if there would be a conflict when both cards want to use com1, if I was to use a splitter instead of the switch.
I am guessing 'first come, first serve'

 

[edfair]

Actually, first come, first to be screwed up. And the second wouldn't work either. And both would get messed up because the handshaking signals would interfere.

If the application would allow it (delay) you probably could put relay points in both serial paths and use a handshake line to control the relays. Same as the switch except no human contact.

Ed Fair
Give the wrong symptoms, get the wrong solutions.