ANL-16-L (16-Port Neon Analog Line)
Issue 4 May 2002
10-81 555-233-123
Loop Around Test (#161)
Each Analog port consists of:
■ an NPE for port connectivity and gain, and conferencing functionality
■ a code that converts the digital signals of the TDM Bus to analog signals
■ a battery feed chip that provides power to the telephone set for signaling,
dial pulsing, transmission, and balance
This test is designed to check the on-board transmission capabilities of the NPE,
the codec, and the battery feed chip of the analog port. A Tone Detector and a
Tone Generator talk and listen on the same pair of time slots as the Analog Port.
The Analog Port is then instructed to go into loop around mode (see the following
below). The test passes if the signal measured by the Tone Detector is within
acceptable limits.
Figure 10-2. Analog Loop Around Test
TONE
LEVEL
MEASUREMENT
TONE
SOURCE
TDM BUS
BFC*
CODEC
NPE*
NPE - NETWORK PROCESSING ELEMENT
TN746B
TN468,
etc.,
PORT
* BFC - BATTERY FEED CHIP
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