• Part of a roofline shows from one building. Trees with fall color leaves on them fill most of the photo. A lamp-post is near center of the photo.

    Harpers Ferry Center

Portable Assistive Listening Device FAQ

Frequently Asked Questions: Portable Assistive Listening Devices

Portable assistive listening devices assist people who are hard of hearing access personal services programs. Everyday ambient sounds can impact everyone's ability to hear a program. Parks are therefore encouraged to offer these devices to everyone, regardless of hearing loss. Below are responses to questions frequently asked about portable assistive listening devices.

Are these systems water resistant?

These systems can be used outdoors. Like a phone or other types of portable electronic equipment, some dampness is ok, but they should not get wet.

Will these systems interfere with park radios?

No, they use different radio frequencies.

What is the range?

Outdoor line of sight for wide-band channels can be transmitted up to approximately 150 feet. Indoor conditions vary based on building conditions. If the group is in one room, they will work.

Is there a theft protection mechanism?

There is no theft protection built into the devices.

Can two or more presenters use individual transmitters on the same channel for the same program?

No, it is not possible to have multiple transmitters on the same channel.

Can two or more groups be present in the same area using different channels?

Yes. Test your channel selections in advance. If there is interference, select a different channel on one of the transmitters.

What is the battery life?

Battery life varies depending on the manufacturer and model. A conservative estimate for continuous play is 20 hours for alkaline batteries and 10 hours for NiMH rechargeable batteries. Cold temperature will reduce times. Alkaline batteries will retain reserve power for 5 or more years. NiMH rechargeable batteries lose about 20% of reserve power per month and should therefore be kept on the charger.  It is always best to turn of the devices when not in use. Batteries can leak, so it is best to remove batteries and store nearby if the device is not used regularly.

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