Frye FONIX 7000 - Manual (Page 74)

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FONIX 7000 Hearing Aid Analyzer
Figure 3.3.6—Eyeglass Aid Set-up
3.3.7 Wireless CROS and BICROS Aids
The key to testing these aids is to get the proper amount of separation between
the transmitter and the receiver. This separation may be vertical. The transmit-
ter may be in the chamber while the receiver is on top of it.
If you are using a CRT monitor, it may be necessary to turn it off while testing
these aids, because CRT monitors create magnetic fields which may interfere
with testing. Either turn the monitor back on to view results, or push [PRINT]
to print. LCD monitors should not cause interference.
Wireless CROS
A CROS (Contra-lateral Routing of Signal) aid consists of a transmitter and a
receiver so that sound received on one side of the head can be transmitted to
the other side without a wire connection. You can test these units in the test
chamber of the FONIX 7000 Test System. See Figure 3.3.7.
1. Place the microphone of the transmitter at the reference point in the test
chamber. Turn on the transmitter.
2. Close the lid of the test chamber.
3. Check the specification sheet of the aid under test to determine how far
apart to place the transmitter and the receiver. About 6" (15 cm) is usually
sufficient.