Telikou BK-105/4 is a single channel belt pack with Tally connector

PTT (push to talk) and Latching Microphone button
Call button; Call light; Volume control
Sidetone adjustment
XLR-4M headset connector
XLR-5 Intercom Cable connector with Tally
XLR-3 TL-2 tally light connector
3.5mm Headset connector