The BS-181 is a single channel Power Supply housed in a steel case. It has the capacity to power up to fifteen BS15 beltpacks to full volume. The BS 181 enables cost-effective system powering or expansion when only one channel is needed or requires expansion. The ASL Basic Series provides a cost-effective solution in more limited applications that require full duplex, party line communication. All interconnections are made with standard, balanced microphone cable with XLR-3 connectors. Installation requires no expert knowledge, and clear layout of controls assures trouble-free operation with a very short learning curve. A current-driven interconnect loop ensures that operator listening levels do not change as stations are added to or removed from the network.