Donald K wrote in message ...
Thanks Donald for your information. It shows, even after 15 years of
scanning, there are even simple things I did not know.
Fred Burgess
_Full_ duplex is where you can both speak and hear AT the same time
(like a telephone).

_Half_ duplex is one direction at a time.

Simplex is both sides of the conversation on the same frequency.

Both repeater conversations and "simplex" conversations are _half
duplex_.

Unless a scanner has two receivers, one cannot hear _full_ duplex on it
(because it involves potential traffic on two different frequencies at
once. (unless you want to talk about sidetone and mean nasty things
like that...))

-D
http://www.m-w.com/cgi-bin/dictionar...nary&va=duplex
2 : allowing telecommunication in opposite directions simultaneously

"http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=half%20duplex"
a mode of communication especially with a computer via telephone line in
which information can be sent in only one direction at a time