Question:  I am a volunteer stage manager for a small middle school theater. We have been using family radio style walkie talkies as our communication system and it is time to upgrade to something that actually works.
I think I am looking for a wired system that can handle 6 stations. All one channel party line. Can you help me specify such a system?
Answer:  Que-Com intercom systems are a compact, cost-effective, portable solution to many intercommunications needs. It consists of a PK-7 intercom power supply, and a choice of either one-ear (SMQ-1) or two-ear (DMQ-2) headset stations with an integral boom mic, attached to a rugged beltpack housing the electronics. Que-Com systems are compatible with all other Clear-Com party-line intercom products. 
The PK-7 power supply is housed in a rugged metal chassis and has the capacity to power up to 30 SMQ-1 or DMQ-2 headsets.  It supplies 24 volts DC at .4 amp to the system. The fully regulated, current-limited unit also provides proper termination for the intercom system. The PK-7 features both short-circuit and reverse polarity protection.
Three separate 3-pin XLR connectors are provided for intercom audio and power output to the headset stations. Use SP-3 line splitters on these connectors to attach additional headsets to the system.  See system drawing below.

Alternatively :you can look at 1x PK-7 system power supply6x RS-601 1 chnl wired beltpacks 6x CC-300 / 400 headsets