The RCM - B series of Room Combining Matrices room combining provide simple combining for divisible, multi-purpose meeting rooms. With the push of a switch they can combine the audio between rooms. The RCM-42B can combine up to four rooms, and the RCM-82B can combine up to 8 rooms. 4 or 8 combining inputs/outputs Each room connected to an RCM-42B or RCM-82B may have its’ own independent audio source or it can share either of two groups in combination with other rooms. This grouping may be changed at any time via remotely wired control switches (see RCM-S two program busses series). These switches can be placed in any convenient location. Magnetic or optical switches can also be used in sliding door pockets to automatically combine rooms when doors are opened. Wiring can signal level constant be unshielded low voltage control wiring. when switching between groups The RCM-42B and RCM-82B are unity gain devices. There is no change in signal level as rooms are switched in or out of a group. These matrices use standard balanced inputs , and can be used with any preamp/amplifier combination. The new B-series has been enhanced with switch common mode rejection, de-bouncing, ESD protection, and an LED on indicator. It now includes a 24VDC wall-mount power adapter.