Clear-Com's EB7-4W 4-Wire Option module can be added to the KB-702, KB-702GM, KB-701, and HB-702 products. This option allows the speaker or headset station to be operated over longer distances than are possible with a standard Clear-Com intercom line. This option can also be used to connect with fiber optic transmission equipment. The EB7-4W 4-Wire Option module connection is a transformer-isolated, audio-only connection and does not convey the call signal. The module also requires local powering. Two-channel stations can have two separate 4-wire connections with this option. The Channel Switch on the front panel selects which channel is connected.