Asterisk cmd Milliwatt

Synopsis:

Generate a Constant 1004 Hz tone at 0dbm ( mu-law )

Description:

Milliwatt()

Generate a Constant 1004 Hz tone at 0dbm (mu-law)

Earlier versions of Asterisk generated a 1000 Hz Tone. If the old behaviour is desired for some reason, use the “o” option. The new behaviour is in 1.4.21 and later; the old behaviour is in 1.4.19.

Details

A “Milliwatt (102 Type) Test Line” is a signal generated from an end office which provides a 1004 (!) Hz tone at 0 dBm0 for one-way transmission measurements towards the customer’s location from the Access Service Provider end office.

Milliwatt test tones are often found at NPA-NXX-0010 or NPA-NXX-9935.

Note that, instead of 1000 Hz, 1004 Hz has been the Telco standard for many a year. The sampling rate on a T1 for a DS0 is 8kHz and 1kHz is a harmonic of 8kHz and harmonic distortion can cause significant measurement errors. So early on engineers tuned the test frequency to be slightly off to keep harmonic distortion to a minimum when taking loss measurements.

You can provide this via simple dialplan logic without using the rather non-standard Milliwatt() application:

exten => 8114,1,Answer
exten => 8114,n,PlayTones(1004/1000)
exten => 8114,n,Wait(300)

See also

• http://www.tech-faq.com/milliwatt-test-line.shtml: What is a milliwatt test line?
• Asterisk cmd Playtones
• Tips & Tricks
• CLI

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