On Fri, 07 Jan 2005 23:29:16 -0600, Cecil Moore
wrote:

|Wes Stewart wrote:
|
| Cecil Moore wrote:
| |A two-wire serial ASCII RS232 line is time-multiplexed between
| |marks and spaces, i.e. you can't have a mark and a space occurring
| |at the same time. :-)
|
| Baloney.
|
|Didn't you ever use an 8 to 1 *MULTIPLEXER* chip to change
|parallel BAUDOT to serial BAUDOT?

Actually, no. I have however, worked on monopulse RADAR missile
seekers where the requirement for three phase and gain matched
receiver channels (sum, delta elevation, delta azimuth) was reduced to
two by time-sharing one delta channel. You can call this multiplexing
if you want (TDMA?), but as an r-f guy, I have a different take. At
any point in time the only data in the delta channel was *either*
elevation *or* azimuth, not both elevation *and* azimuth. (* maybe a
digital system after all? :-)

|The parallel BAUDOT bits
|are time-multiplexed into a serial bit stream by the
|three clock bits. The first parallel bit is hard-wired to
|yield a start pulse and the last two parallel bits are hard-
|wired to yield a stop pulse. The center five parallel BAUDOT
|bits are time-multiplexed from parallel to serial by five
|states of the clock.

Fine, but how does this support your statement above to which I
responded?

I think I'm catching on tho...in ham terms, a digital multiplexer is
like a two-meter repeater; only one guy can talk at a time. I'm more
familiar with analog multiplexers, a 20-meter DX pile-up for instance,
where everybody talks at once. [g].