User's Manual

1� Switched B+: Used to automatically turn on/off Wire-
less Speaker Microphone if connected to host radio
switched B+ output, if not, the user should supply man-
ual on/off switch. Note: internal speaker microphone
battery will still charge when the unit is turned off.
2� External Mic Audio: Audio from the Wireless Micro-
phone that is to be transmitted over the host mobile
radios transmitter. It is factory set for 80mV RMS.
3� Radio Mic Lo: This is microphone audio ground.
4� Receive Audio: Receive audio from the host mobile
radio that you wish to be sent to the Wireless Micro-
phone. Ideally it should be sourced pre-volume con-
trol but can be post as long as the host mobile radio’s
speaker audio has been sent for comfortable listening
in the vehicle.
5� Power: connected via a 1 amp in-line fuse preferably
direct to a vehicle’s 12V battery but can be any volt-
age from about 6-15VDC. The current consumption is
typically 60mA with peak current of 420mA.
6� Ext� PTT: Switched ground output designed to cause
the host mobile radio to transmit.
7� Emergency: Output intended to connect to the host
mobile radio’s emergency input. It is normally provides
an active switched ground but can be jumpered to be
active open circuit/high. The time held low (or high) is
the exact time that the user presses their Emergency
button. This output could be used for other functions
such as to trigger the panic function of a car alarm
system, providing it is correctly “buffered” so as to not
cause damage to the mobile charger.
8� COR/squelch/audio unmute: Input designed to moni-
tor the receive status of the host mobile radio. Ideally,
it is driven by an “audio unmute” command in the host
mobile. i.e. when the radio’s speaker unmutes to pass
audio then the COR input should toggle in sync.
Installation & Connections
15