The 312B-5 Station Control/PTO allows for split frequency operation when connected to the KWM-2/2A.  The PTO control selector can be set as follows: (1) Receive KWM-2/2A, Transmit 312B-5;  (2) Transceive  KWM-2/2A;  or (3) Transceive 312B-5.  Like the 312B-4, it has a 5"x7" magnetic speaker, RF directional wattmeter with 200 and 2000 watt scales, and a phone patch. Size: 10" wide, 7 3/4" high, 12 1/4" depth.  Weight 8 1/2 lbs.