CM-TBU, Telephone hybrid. Phone hybrid for analog phone line powered by the line. Connection for telephone line and telephone on RJ-11 connectors. Balanced (transformer) input and output on XLR connectors. Balancing the line is done manually. In and out level adjustable via pot. on the front. Sidetone rejection normally at 30-40 dB. Size: 77 x 83 x 42 mm.