[RTTY] RE: second soundcard

K4SB hamcat@directvinternet.com
Mon, 08 Jul 2002 17:58:23 +0000


WA9ALS - John wrote:
 
> I'm no expert on this, but N1RCT's old RTTY web site had a little discussion
> about this.  He made the point that FSK/PTT -only- transmit data and can
> share a com port (IRQ) with something else.  In Bill's example, the "usual"
> would be for COM 1 and 3 to share the same IRQ - Com 1 is rig control, but
> COM 3 is only for CW keying.  A similar analogy is present for COM 2 and 4.
> I've shared COM ports before like this, especially a modem and an FSK/PTT
> cable.  I would think that rig control would be more demanding  (tx/rx) than
> a modem, especially fi the modem were not in use.  I'm sure the modem and
> rig control couldn't share the same com port, but some of these cables we
> make for fsk/ptt/cw -can- share with other devices at times.

This can be done in Windows also, but choices are limited. For
example, LOGGER, by K4CY does this with PTT and Radio Control. As Bob
once explained it to me, When the PTT command is sent, another command
is sent to bypass the entire rig control program. In other words,
don't interrogate the radio.  Normally, Rig control is active and PTT
is just checked during the cycles. Logical, since you hardly need Rig
Control on transmit.

Good stuff from John.

73
Ed