In article ,
Thomas Borchert wrote:

Ingo,

Does anybody know portable expanders to
plug 4 intercoms into an builtin 2 place-Intercom.
I sometimes rent aircrafts having only a two-place
Interkom but would like also to speak with the
passengers.


The solution is to plug a portable 4-place-intercom into the pilot side
of the built-in intercom and plug all headsets into the portable. The
disadvantages a

- A built-in PTT on the copilot side will not work
- The built-in PTT on the pilot side will work, but everybody speaking
on the intercom circuit at the time will get transmitted.

Be careful! You may get interference when you transmit or you may get
interference on one of the intcoms from feedback.