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.