atcomsystems.ca/forum Forums TDM Business Telephone Systems Mitel Telephones & Systems SX-50 calls dropping but only during night time

Hey I'm very new with phone systems so please bear with me.

We have a Mitel SX50 phone system at a hotel with 4 trunk lines. We had verizon before and everything worked great. We switched over to time warner cable about a month ago and now we have calls dropping (after 1 to 30 seconds) but the problem only happens at night. The TWC technicians came and checked everything saying everything is working great on their end.

Do you guys have any idea what the problem could be?

Did you have ground start trunks with Verizon? If so, did you convert the trunk ports over to loop start when you switched to cable? You can't just switch trunk types without doing the same within the SX50. I seriously, seriously doubt that TWC is providing ground-start.

Regardless, that wouldn't cause a timed problem. It would be all or nothing. Still, I would think that most outgoing calls are being made from a hotel at night. I don't know a huge amount about Mitel, but perhaps it allows a call for a certain amount of time before it realizes that the trunk type is wrong?

Also, the hardware that CLECs use often doesn't provide the precise 48 volt trunk voltage that is required for proper supervision. I'm going to guess that they are using an Arris box that only puts out between 24 and 32 volts on the trunk ports. If that is the case, you have an open and shut claim that it is a trouble on their end.

Are the calls routed to a different answer point at Night?
Maybe that particular device is having a problem?!?!

Ed is probably correct. Mitel's don't play well with the 28-32 volt 'lines' that most of the TWC units work with. Make them prove that the on-hook line voltage is 48-52 volts.

Also, have them check for call waiting on ALL the lines! YOU DO NOT WANT CALL WAITING. Mitel see's CW as a disconnect signal, and it disconnects.

So...what everyone is saying....it was working before TWC and it doesn't work now. How much money did the TWC salesman say the TWC lines were going to save?? :shrug:

@JWRacedog: The phone systems work during the day time but around sundown calls start to drop, sometimes we get 5 seconds of talk time, sometimes we get 45 seconds of talk time, it's completely random. Then around sun up, the phone systems work perfect. We actually saved a good amount of money so I'd really like to stay with them.

@Lightninghorse: I just checked with TWC tech support, call waiting is already disabled on all lines. Also they don't know the voltage on the lines but they know its transmitting at "48 decibels"

@fifty5footer: The calls arent routed differently based on time, to the best of my knowledge. All calls go to the front desk regardless of time unless they turn on night mode, which has always been off. I'm going to try a test by changing the time on the switchboard to 3:00AM and see if calls start dropping. If they do then I'll know its a problem on my end for sure.

@EV607797: I'm not sure about the ground/loop start trunks, but since its working during the day time it shouldn't be a problem with that right? I'm not sure about voltage but according to TWC tech support they are transmitting at "48 decibels"

When the phones are working correctly during the day I'm going to change the time on the switchboard and see if that has any effect (in case its routing the calls differently during night time). If it starts to drop calls after I change the clock on the switchboard I'll assume its a problem on my end.

One last thing to note, we have internet and phone with TWC, internet always works fine but phones have problems (only at night though)

I'll keep you guys updated, but if you guys can think of any other reasons this may be happening then please let me know. Thanks so much for all your help! Have a great thanksgiving!

Only at night-when everyone is trying to use the internet...

FYI, 48 decibels is an unbelievably loud level. Incoming calls usually in the neighborhood of Minus 6 to Minus 8 decibels. Obviously 'tech support' has no clue!

The ONLY way TWC is going to find the problem is when it is happening, AT NIGHT.

AS westerntelephone says, "Only at night-when everyone is using the internet." You probably have a "dynamic" connection. This means that the actual number of trunks is inversly proportional to the amount of internet activity, on the feed that you share with ??? knows how many homes and business's. THIS IS A TWC PROBLEM!

I was at the business today looking things over, the problem started again around 5:50. I tried changing the time on the switchboard, it didn't do anything to fix the problem.

One other thing I haven't mentioned yet is how we have a fax line + 4 trunk lines. The 4 trunk lines are connected to the switchboard but the fax line is completely separate. The fax line works all the time, it never drops a call. So maybe it isn't a TWC problem?

"according to TWC tech support they are transmitting at "48 decibels"

Such a statement is indicative of a 'technician' who doesn't have a clue what they are talking about. This technician needs to understand that trunk voltage and transmit levels are completely different issues. This genius also needs to connect a voltmeter to the trunk ports at your premises and show you that the voltage is beween 48 and 52 volts DC when on-hook. If they can't prove this, then you win the battle.

Oh, and as for the matter of the fax line: Fax machines are much more tolerant to line voltage inconsistencies. PBXs are designed to work with precise line (trunk) voltages. This is a standard that has existed for many, many decades.

If each trunk cannot provide ~48 volts DC between tip and ring and between ring and ground, then you do not have true PBX trunks or even POTS lines for that matter. Please copy/paste this paragraph and show it to TWC.

You need to seriously think about this: Is TWC really saving you any money? They have already proven that they don't know what they are doing. Your SX50 was working fine until they entered the picture. Now all of a sudden your system is causing the problem? Yeah, OK..........

Come on, stop and look at the big picture. I'd go back to Verizon and find other places to save money. CLECs don't follow FCC standards (despite the fact that they are supposed to). They offer cheaper rates by tossing their customers under the bus when something goes wrong.