[nos-bbs] Comm ports

[Mark Phillips]

It does indeed work with any com port that you can address. The problem
is that of IRQ interrupts.

Commonly on a WinBlows/DOS machine coms 3 & 4 share the same interrupts
as coms 1 & 2. this would mean that first come would be first served in
the JNOS world. In other words if you load up com1 and then com3 com1
will work fine but com3 will not be able to talk.

The way around this is to move the interrupts for coms 3&4 to ones not
in use by the system. Coms 5 & 7 are good choices assuming you don't
want to use a sound card or the printer port.

Perhaps the best choice would have been to look out for a Chase
multiport serial card with IRQ management. This device allows the
supplied 8 serial ports (all with different base addresses) to use the
same interrupt (usually IRQ10). It handles the IRQ competition via its
firmware.

Another alternative would be to use Multidrop KISS (BPQKISS) from a
single serial port (assuming all Z80 based TNC's). Each TNC lives on a
serial network and is polled by the host. One can have up to 16 tnc's
connected to a single host. This is how it works here at KC2ENI.

Hope this sheds some light on things.

Mark

On Sun, 2007-03-18 at 14:54 -0500, Jerry and Michele Groeneveld wrote:
> I'm setting up a back up computer for the club DOS JNOS system. The new 
> computer is Windows XP that comes standard with COM1 and was ordered 
> special with a dual COMM port card that automatically configured as COM4 
> and COM5. JNOS runs just fine on COM1. But it does not work with COM4 or 
> COM5. COM4 and COM5 talk with the tncs in terminal mode using 
> HyperTerminal. COM2 is reserved and cannot be used. COM4 and COM5 use 
> shared interrupts. I have turned on the dtr and rts parameters in JNOS. 
> I have placed in the attach statements the interrupt and address of COM4 
> and COM5.
> 
> Does JNOS work with ports other than COM1 and COM2?
> 
> Are there JNOS parameters I should setup?
> 
> Thank you,
> 
> Jerry, N0MR
> 
> 
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