PM-660U
The device shall be a low impedance, dynamic microphone with an integral stand and base
suitable for desk and shelf mounting. Nominal sensitivity and impedance shall be -58 dB at 1k Hz
(ref: 0 dB = 1 V / Pascal), 600 ohms, balanced. Frequency response shall be from 100 to 10k Hz
with a cardioid directivity pattern that is uniform over the entire frequency response range. A
push-to-talk bar shall be mounted in the base with a locking lever to permit locking the bar in the
microphone on position. The bar shall actuate two long-leaf, spring-type switch contacts. One
shall be a normally closed contact that shorts the microphone element in the microphone off
position. A second dry contact shall be provided for use with external muting, priority or relay
circuits. The second contact shall be normally open with the microphone off. An attached 8.2’
cable shall be provided with two shielded conductors for the microphone audio and two
unshielded conductors for the auxiliary switch contact. The cable shall be supplied with stripped
and solder-tinned wire ends. The microphone stand/base shall be constructed of dark gray, ABS
resin plastic with a zinc-plated steel mesh head for the microphone element. The head shall have
a baked gray paint finish and an internal windscreen. The push-to-talk bar shall be orange with
TALK engraved on its face. Dimensions (W x H x D) shall be 3.9" x 8.5" x 5.9” (99 x 216 x 150
mm) and weight shall be 0.97 Ibs. (0.45 kg).

The microphone shall be TOA model PM-660U.