DRAFT 2.0 – COMMERCIAL IN CONFIDENCE
FST DT-5365 Series Installation & Service Manual T/18237 Draft 2.0 Page 14 February 2018
3.2
EARPHONE (3.5mm Four Pole)
For iPhone or Samsung Smartphone Earbuds with mic
Pin Number
Description
Level / Sensitivity
1 (mic)
Mic Tx audio
-34dBm nom., 5.6V bias
2 (sleeve)
Ground
0V
3 (ring)
Right Rx audio
-10dBm nom. User adjustable Rx Level
4 (tip)
Left Rx audio
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3.3
HEADSET (RJ9 also correctly called RJ22)
For Plantronics HW251N or H141N Headset
Pin Number
Description
Level / Sensitivity
1
S
Speaker drive -10dBm nom.
(User adjustable Rx level)
2
Microphone -
Microphone return
3
Micr
-34dBm nom., 5.6V bias
4
Speaker -
Speaker return