analog extension voltage problem

[natemgt]

My customer has a SX200ICP system. I am getting anywhere from 22-24vdc on my analog extensions. It is coming off ONS cards and even my ASU. Random ports on different bays will jump up to 90vdc-150vdc and back down, it happens almost like clock work and then it will stop.

I checked technical specs for ONS class line cards should be 48vdc. What would be causing such a low voltage.

I lose ports on this system constantly, I think probably due to the low voltage.

Any help would be appreciated.




This is what was in SX-200 ICP Technical Documentation:

ONS Lines
The ONS line circuits connect standard telephone sets with total combined DC resistance of the set and line not exceeding 600 Ohms. As such, the ONS line circuits are used to connect internal telephone extensions close to the system.
The ONS line circuit has the following features:
• Loop start POTS line with constant loop current mode in normal off-hook condition.
• On-hook signal transmission for CLASS function.
• Balance ringing.
• Hardware ring tip.
• 48V tip and ring DC voltage in on-hook state.
• Off-hook detection by loop current.
• Software-controlled AC line and Balance impedance setting.
• Software controlled audio gain settings in both transmit and receive path.

 

[sarond]

Not familiar with SX-200 but usually the voltage jump of 90v-150v is caused by message wait on the port. It activated the message light on analogue handsets,

I know some systems will have voltages on analogue ports in the range you suggest but I'm not sure on SX-200.

 

[nytalkin]

you must be measuring the voltage with the phone off-hook which will indicate 24 volts. The spike is most likely M/W (see above)
Are you experiencing a particular problem that has you looking for line voltae. OPS interfaace cards will provide 48 volts for specific applications but only in 2000 per nodes.

NO GOOD DEED GOES UNPUNISHED!

 

[natemgt]

I have been measuring in an on hook matter. I have used both my voltmeter and my "butt" set, which is a fluke that has an LCD panel that shows the line voltage across tip and ring before I go off hook.

That measurement for the message waiting makes sense. I had moved the extension that was having that voltage spike to another port and the spike went away.

My customer has many off prem buildings and it seems this lower voltage may have something to do with losing ports.

I went in and enabled option 402 for long loop off prem extensions, but it didnt increase the voltage.

 

[kwbMitel]

SX-200's have OPS Cards as well. There are 6 cct's per card rather than the standard 12 which is how they double the voltage.

The OPS card part number 9109-040-000 is only supported on the MX Platform with an ELx Peripheral Bay

The distance limitations for each card is:
[tt]
External Loop Length for ONS:
22 AWG (23 IWG) 3560 m (11700 ft)
24 AWG (25 IWG) 2250 m (7400 ft)
26 AWG (27 IWG) 1400 m (4600 ft)

External Loop Length for OPS:
22 AWG (23 IWG) 15240 m (50,000 ft)
24 AWG (25 IWG) 11520 m (37800 ft)
26 AWG (27 IWG) 5850 m (19,200 ft)[/tt]




**********************************************
What's most important is that you realise ... There is no spoon.

 

[natemgt]

to kwbMitel,

thanks for that info,
well those distances for the ONS cards fall within the other buildings...

I'm still concerned about the voltage I'm seeing, is that normal?

 

[kwbMitel]

24v DC is normal for ONS.

The other voltages that you are seeing look like ring voltage.
Toggled ring voltage is used for message waiting.

Very few devices have any issues with these values.

The most common device that has issues is a Point of Sale device. These devices typically have a "Line Check" that looks for a threshold voltage to verify that a line is active or live.

An Active line would have about 7v Dc for talk battery
A live line could be dtermined to be one in excess of 10v Dc.

Unfortunately, these devices look for a voltage in excess of 30v Dc. As Such, they think the line is dead when connected to a Mitel ONS port. Most of these devices can have the Line Check feature disabled and this resolves the issue over 90% of the time.


**********************************************
What's most important is that you realise ... There is no spoon.