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Milliwatt

Posted by voip on Sun, 12/16/2007

OK, another super simple script anyone can write that should be included with Thirdlane PBX because it's handy. Voip-info says this is a 1000Hz tone. A milliwatt is officially 1004Hz. My analog meter says it's 1004Hz. In either case it's a handy test to have available. I have it ring for a moment so if I'm not measuring it with a meter and using a phone I have a moment to know it's connecting and get it away from my ear before it blows me away.

Add it to your list if you find it useful.
Jim

;=========================
; silly little useful script
; answers and plays a 0db 1004 Hz tone
;=========================
exten => s,1,answer
exten => s,n,ringing
exten => s,n,Wait(3)
exten => s,n,Milliwatt()


Submitted by voip on Mon, 12/17/2007 Permalink

I'm old school. In the pre-IP days you NEVER turned up a TDM circuit without measuring the transmit and receive levels at the analog point to assure good voice quality. If you passed on doing this and verifying echo and impedance settings you might as well go park your service truck and go sell donuts because you were giving people back quality calls. :-)

I have an analog meter that bridges up with the tip ring connection and will use it to measure loss or gain and tweak the settings if necessary.

[Asterisk server, milliwatt @0db] --(SIP)---> ATA (FXS or FXO) --> level meter

The milliwatt IS the industry standard tone for doing just this. THANK YOU Asterisk for providing this application! I'm just still old school I guess but it's hard to walk away not verifying these things TDM or IP...

If you did this and used the echo test you can be sure to tweak an analog supported device to their best performance. At least you will walk away knowing what to expect in call quality.

Jim

Submitted by voip on Mon, 12/17/2007 Permalink

Oh, I forgot to mention I will also use it for a quick call thru test after plugging in a new phone. That's why I want it to ring so I can get the phone away from my ear as the tone is LOUD and can easily be heard with the handset laying on the user's desk.

I have one setup in my own Asterisk switch with a DID pointed at it I have used for PSTN call-thru testing from a client's site.

Jim

Submitted by eeman on Sat, 12/22/2007 Permalink

because milliwatt is a constant unchanging tone it work as a good diagnostic to troubleshoot. You can call a milliwatt app from a sip phone and listen for jitter etc. Since its a constant tone its easy to hear disruptions caused by jitter or packet loss.