9
Audio Output
Minimum load
impedance
16 ohms
Audio output
DC coupled
Connector
2.5 mm mono-audio jack, tip
is output, sleeve is ground
If the audio out load impedance is at the minimum (16 ohms)
some decrease in volume at the speaker within the unit can
occur. To avoid this, connect the audio out to a load of several
hundred ohms.
AUTO-REGISTRATION AND OTHER SHORT
TRANSMISSIONS
Cellular telephones communicate with the cellular network by
sending short duration transmissions to identify their location
within the network. These transmissions are called
Auto-Registration signals and can occur anytime the cellular
phone is ON.
For analog cellular phones these Auto-Registration signals
occur about every 30 minutes and last for only about 125 ms.
When a cellular phone is turned on it checks an internal
counter to see when it last sent this signal. Only if 30 minutes
has passed, or the phone has moved into a new cell, will the
cellular phone emit an Auto-Registration signal within the next
few seconds.
Cellular phones that use one of several digital formats as well
as PCS phones may register less often than an analog phone.
Some only register at the time the phone is turned off. Also,
cellular phones respond when they are paged for an incoming
call. They do this by sending out a short message similar to a
registration signal. This tells the cellular network that the phone
is ready to take a call and a ring sequence begins.
Summary of Contents for CellPhone Detector Plus
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