KRETSANORDNING FOR UPPBYGGNAD AV HUVUDLINJEKRETSEN FOR TELEFONBICENTRALER, SPECIELLT FOR DIGITALA BICENTRALER
摘要
A trunk circuit comprises a dialled digit sensing transistor 2 controlled with optical coupling, CS1, a muting relay A, optical coupling CS2 connected to the coil of the muting relay and a dial pulse control circuit 6. <IMAGE>