atcomsystems.ca/forum Forums TDM Business Telephone Systems Mitel Telephones & Systems Mitel sx50 alarm no trunk release

I have a mitel sx 50 that is throwing an alarm no trunk release the book said is a reversal, or programed as a ground start trunk, Trunks are programed as loop start, I have reversed the trunk polarity and have set the trunk for no reliable disconnect, every time a call compleats the trunk stays lit in the card then busys out, I have also replaced the trunk card with the same results. Help please

I'm not Mitel savvy.

Having said that...if the trunks are stand alone POTS lines...has the LEC been contacted to have Positive Disconnect (or whatever they may call the feature) activated on the trunks

Do you have dial tone on the line? Is it loop or ground start?

Did you move it to another port with the same result?

all ports are acting the same way and they are loop start

and if I didn't have dial tone I would know the problem----

all right stumped tech support wooohooo

Stumped? LOL

First, have you taken measurements on the trunks yet? Voltage, current and readings between ground and tip and then ring. The voltages you should see on a normal POTS central office trunk are -48 VDC between tip and ring when idle. The voltage should be, somewhere around -7 VDC off hook. The current should be in the range of between 25 to 35 ma. Check the voltage during a call and then stay on the line with your VOM as the call is terminated. What is the condition after the call is terminated? Check all these measurements with the trunk card installed and then remove the trunk card and make the same measurements with your butt set.

If this condition just happened, I would look at telco changes. Did they migrate from copper to fiber or maybe a T-1 with a channel bank? The SX-50 is forgiving of a lot of abuse, but if you have a high AC influence on the circuit, the problem you describe will occur. We service a motel in the sticks with a long line run from the CO and, from time to time, we see this exact same condition. A call to the telco gets another patch job and the trunks work for another 6 months.

Look for AC from ground to tip and ground to ring after the call is terminated. There should be none. Also, check your local system ground and the telco cable ground. There should be zero ohms or a very low ohms reading between your system ground and the telco cable bond ground.

Stumped? No. Lack of info? Yes.

Rcaman

The lines are POS internet lines from the cable company who metered them while on site but they are a bunch of liars. will check myself thanks for the help

Ah...should have mentioned that first. We have had many, many "discussions" with cable companies regarding their "idea" of what is standard telephone line parameters and what is just not workable. They need to replace their modem. Unfortunately, we have to deal with Comcast here and that is what has been done time and time again when this problem occurs. Mitel is especially finicky with regards to telephone line parameters. Get the cable company out there and tell them you want standard telephone line conditions on the trunks with which you are dealing. I have provided you with the basics. If they meet, at least, those, your system will work.

Rcaman