Monitor
The Monitor section of the earplug allows you to listen to and meter an incoming signal.
With the Mode switch in the Sig or Mic position, the Monitor input has 0db gain.
With the Mode switch in Amp the monitor input has 20 or 40db of gain depending on the position of DIP 1
The monitored audio will be metered by the bargraph meter on the front and the calibration of this meter can be adjusted using the D preset revealed when you remove the four M3 screws on the bottom of the box. Factory calibration is 0dbm (775mV into 600 ohms) corresponding to 0 (Yellow led) on the meter.
Monitoring of this audio is via the internal speaker (Quantity Monitor) or via the headphone jack (Quality Monitor). The headphone jack can accept stereo or mono headphones quite happily and will disconnect the internal speaker when a jack is inserted.
You will also be able to see the level of the test signal on the LED meter on the front panel. This has a response that emulates the standard BBC Peak Programme Meter. If you need to listen to a Mic level signal then you can switch the Modeswitch to Amp which will insert 20 or 40dB of gain into the Monitor section. For more on this see the Mic Amp page
Please be aware that the earplug can generate signal levels in an earpiece or headphones that could damage your hearing. The manufacturers can accept no responsibility for injuries caused in this way. You have been warned!
Imagine the situation...
You are rigging a communications unit for which you are expecting some line level feeds which aren't apparently reaching you. You connect the earplug to the end of the offending cable and switch it on.
Get the person on the other end of the cable to send you a known test signal (possibly using another earplug!) and adjust the volume control on the top of the unit. You should hear the signal from the loudspeaker (or if you need to operate in "stealth mode" insert a pair of headphones and listen to them. See the disclaimer above).