background image

Hearing Helper

Personal FM Receiver • 

Model PFM R31

Hearing Helper

Personal FM Receiver • 

Model PFM R31

©2007, Williams Sound Corp.  MCAT 005B

1

NOTE: SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE!

Description:

Maximize a student’s ability to listen with the Personal FM R31 receiver from Williams Sound. The
PFM R31 will ensure that everyone in the classroom can hear the speaker’s message clearly and easily.
Each receiver has a range of up to 150 feet, and will operate up to 80 continuous hours.  Versatile 3.5
mm jack allows for a variety of earphone and headphone options, or, equip it with a neckloop to
make it compatible with most telecoil-equipped hearing aids.

The PFM R31 features a sensitive environmental microphone which gives the listener more flexibility
on what they want to hear. By turning on the environmental mic, they can listen to a nearby class-
mate speak more clearly.

Applications:

Classrooms • Job Consultation • Job Training • Tours • Group Meetings

Dimensions:

3-5/8" L x 2-3/8" W x 7/8" H  (92.1 mm x 60.3 mm x 22.2 mm) 

Weight:

4.6 oz (130 g) with batteries

Color:

Royal blue, shatter-resistant polypropylene

Battery Type:

Two (2) AA 1.5 V non-rechargeable Alkaline batteries (BAT 001),
14 mA nom. current drain, 80 hours approx. life
(OR) Two (2) AA 1.5 V NiMH rechargeable batteries (BAT 026), 
14 mA nominal current drain, 50 hours per charge approx.,
recharges in 14–16 hours, uses CHG 200 Charger

Operating Freq’s:

Pre-tuned, field–tuneable, 72 MHz - 76 MHz*. 
Pre-set channels are E (72.9 MHz) and G (75.7 MHz).

FM Deviation:

Wide-band, 75 kHz, 75 µS de-emphasis

AFC Range:

± 120 kHz

Sensitivity:

4 µV at 12 dB Sinad with squelch defeated, 
squelches at 10 µV for min. 50 dB S/N ratio

Freq Response:

100 to 10 kHz, + 3 dB

Signal-to-Noise Ratio:

50 dB at 10 uV

Receive Antenna:

Integral with earphone cord

Audio Output:

35 mW, max. at 16 

Ω

Output Connector:

3.5 mm mono phone jack

Squelch:

Set to turn off audio under weak or no signal condition

Carrier Detect Ind:

Red LED, turns on in the presence of a carrier 

Controls:

Volume: Rotary, 

On/Off/Volume

Tone: 

3-way slide switch; Lo: flat response (20 Hz), Mid: -3 dB at 235
Hz, Hi: -3 dB at 730 Hz

Channel: 

2-way slide switch; Ch 1 = 72.9 MHz, Ch 2 = 75.7 MHz

Indicators:

On/Off and FM

Mic Connector: 

3.5 mm mono phone jack, supplies positive DC for Williams
Sound electret mics

Microphone:

Plug mount electret, omnidirectional, with windscreen, 3.5 mm
mono phone plug (MIC 014)

Mic Volume:

Rotary control

Note:

Specifications are electrical performance

Approvals:

FCC, WEEE

Warranty:

5 years, parts and labor**

PFM R31 FM Receiver:

R31 Top

R31 Front

R31 Back

EAR

MIC

FM

Mic

FM

On

Min

Max

Off

Max

On

Indicator Mic

Volume

Mic Jack

FM

Indicator

FM

Volume

Mic

Jack

  Williams Sound

Hearing Helper

®

Tone
Control

Channel
1 or 2

**90 days on accessories.

*DISCLAIMER: FCC RULES LIMIT USE OF THIS EQUIPMENT TO AUDITORY ASSISTANCE
FOR THE HANDICAPPED.

Reviews: