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.
