网上说是电申容咪
the icom sm-20 is a unidirectional, electret microphone designed for base station operation with many icom transceivers. (it cannot be used with non-icom transceivers since the power is supplied from the connected transceiver). the sm-20 features up-down tuning (on compatible icom transceivers). there is a switch for ptt (push to talk) and also a lock feature.
on the bottom of the mic base there is a gain adjustment and a low cut switch. this mic is powered from the icom transceiver. the mic cables terminate to a standard icom 8 pin mic plug. this mic works with the 718, 746, 746pro, 756, 756 pro, 756proii, 756proiii, 775, 781, 820, 821, 910h and 920.
the sm-20 can also be used with the 706 series with the addition of the optional opc-589 mic adapter cable.
