> The manual for CT suggests some non-standard interrupts for IRQ
> assignments to avoid conflicts: COM1=IRQ4, COM2=IRQ3, COM3=IRQ2,
> and COM4=IRQ5. Since many of the devices will be trying to
> operate simultaneously (e.g. packet connections, networks, rig
> control lines) having the comports on different IRQ's is essential
> to keep from locking the system.
The information thus rendered about separate IRQs for each COM
assignment is exactly right. Note that in some systems, IRQ 2 won't
be recognized, and you may need to use IRQ 9 instead (they are sort
of equivalent).
Be careful in talking about "standard" IRQs for COM ports. COM 1 & 2
are indeed defined as IRQ 4 & 3 respectively, but no other COM ports
are "defined."
Note also, that when using COM ports (and associated IRQs), the
software must support that definition as well. A good example is
ProComm for DOS (the shareware version). You could use COM 3 or COM
4 with it, but you had to use IRQ 3 or 4 (respectively) to do it.
Thus, it wasn't *really* capable of using COM 3 or 4.
73, Rod N4SI
The DXer formerly known as N9AKE
(c) 5 November, 1996
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