atcomsystems.ca/forum Forums TDM Business Telephone Systems Mitel Telephones & Systems Strange behaviour Mitel 3300 + 5220 / 5224

Hi y'all, at this wonderful Forum. My name is Sander, working s a system engineer at a large logistics company in the Netherlands.

We're using 3 Mitel 3300's i.c.w. 5220's and 5224's. Most of the time, lets say 95% of the time, all works well no issues whatsoever.

But then, at random moments an also random subset of 5220's & 5224's lose their display letters.. the inline power is still granted via PoE, so the display is lid up but it is blinking softly, and no letters in the screen with that.

Solution : reset the phone

Has anyone come across such an issue be it with either a Mitel 3300, or with the 5220 / 5224 series voips?

When it happens, chained PC's also lose their network because of this phone behaviour.. and because of the large intervals between these moments the urge isn't really that big.

Nonetheless, i'm still very curious to what this could be. Haven't read/found a single topic on it.. ussually not a good sign :-)

First check your licensing and make sure that you have enough licenses for all the IP phones. If you have, say, 8 licenses and 10 phones, there will always be two phones that are trying to steal a license or else cannot come up.

If that is alright, map your network and see where the problems happen in the network. Is there a location/network issue, for example, do all the affected phones come off of one switch?

Are there network chokepoints? Depending on compression, you could be using 12-56 Kbps per phone call. If all salesmen spend from 0800 to 0900 making cold calls, and they all go through a small "pipe," that could do it.

It would be worth your while to call out the technician who installed the system, and to discuss the issue with him.

Hi there!

Thanks a lot for your reply, there's a few things from it we're certainly going to check.

We indeed suspect a certain chokepoint in the network, mostly the set of phones is in one location ; better said, at one switch, but not all of the times.. I'm suspecting a Qos issue somewhere when uplink is going from 100 to 1000 mbps, or vice versa.

Good hint on the licenses, I'll pass this on to the techguy.

Have you looked at the logs in the 3300 as to what they say about the sets? Are you using Cisco switches? There is a setting in those that needs to be turned off or this kind of problem happens. I have found at one site that the switch in question does not even have to be directly associated with the phones but just on the network. It has been a while so I don't remember what that setting was but it had to do with moving a phone from one location to another and emergency information. Maybe someone will remember this.