Ingo Wolf wrote:
Hi,

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.

I just use a 4 place portable. Your options are to
plug it into the copilot position, or just bypass the
onboard intercom entirely and plug all the headsets
into the the portable and then the portable plugs into
the pilot jacks.