Ls Trunks het lockout " Help Please "

[gimitel]

Hi there Mitel friends,
I have an issue that the Ls trunks on my Mitel 3300 Cxi gets lockout. To unlock them i have to unplugg and then plugg them again at the Analog Option Boards card. This happens when a callers calls in into the MLAA and if the users didn't pickup the phone, for some reasons the system doesn't release the trunk to become free to be able to receive incomming calls.

The caller at the other line closed the call, but the system keeps ringing the trunk untill some picksup the phone. after that the line becomes free!!
Another example is the i use the Business Hour List. I called the number i do get the MLAA that the company is closed. After that the Ls trunks get lockout/busy. I have  to unplugg/ plugg the line from the LS trunk so i can receive calls.

I tried line reversal at the Co Discriptor but nothing. This is making me crazy.
Can someone help me out

[x-man]

This is the diconnect clear time setting that is incorrect. The timer needs to be set slightly shorter than what your line provider has set theirs to. For instance in the UK its set at 100msec by BT and we usually set to 66 msec, unless its a feature line when BT set it to 800 msec a dn we set to 600 msec. Trunk Circuit descriptors is where you will find it.

[gimitel]

Hi there x-man. I check the tip and ring and all if my line where reversed. Tomorrow i will change the polarity (Line reversal) of the lines and then i will test it again.
If not i will shorter the disconnect timer. I will reply tomorrow

[ralph]

I'm betting on the disconnect timer.

Ralph

[gimitel]

well guys didn't change them yet. I have one question, what is the minimum value for the disconnect timer ?

[x-man]

You need to ask your line provider what they have them set to at their end and then reference them to that. 60 msecs is mininum on the 3300 IIRC.

[tomj]

If you are using embedded LS, ASU or ASUII Combo trunks with regular two (2) wire telephone lines and are outside the UK or NA then the PTT/CO is probably using "busy tone" disconnect rather than line reversal or line break disconnect.

Make a call using a regular phone, monitor the trunk line and listen for tones when the caller hangs up to confirm.

If you hear “busy” tone then you will need to configure “CO Tone Detection”

There are a bunch of tones with the (CD) support directory, otherwise you will need to anaylise the frequency and on/off cadence.

This is tricky but works really well.

[ralph]

If you hear “busy” tone then you will need to configure “CO Tone Detection”

Thanks for the imput, tomj.
This is something I've never done before.   Can you point us to where that is set for a CO line?

Ralph

[tomj]

In the UK the serving telephone exchange sends a line break disconnect of approx 500mS when the calling party (who controls the call) hangs-up. The CO Trunk Circuit Descriptor “Disconnect Timer” should be programmed accordingly i.e. lower than this value.

Whilst some public telephone exchanges use “line reversal” disconnect supervision “busy tone” disconnect is by far the most common form of disconnect supervision elsewhere. This is easy enough to identify, connect a regular phone to the phone line, answer an incoming call, hang up at the far end and listen for tone(s).

If you’re lucky the phone company will confirm the tone(s) otherwise you will need to record and analyse the tone to establish the tone(s) frequency and on/off cadence. One way is to set-a voicemail box, ftp the message and use a freeware program to analyse. Once you know the tone you need to configure and enable CO Tone Detection.

There are some examples in the MCD Software Product_Support\COTonesDet directory

Note CO Tone Detection is only supported on embedded and or ASU trunks and NOT on the LS/GS Trunk Card. You need to be reasonably accurate when measuring the tones, when configured correctly it WILL resolve hang-up issues.