ASL PS 29 M is a portable, wired dual-channel analog intercom beltpack housed in a rugged metal case with a steel belt clip. Each channel provides a listen-level control plus TALK and CALL controls/LEDs. It connects to ASL party-line systems via two XLR-3 connectors (one per channel) and receives DC power and intercom signaling on the same two-conductor shielded cable using current-drive transmission. Power is supplied on the line (+30 V DC, 12–32 V).