I've had problems with FAX detectors not seeing ringing from an ATA, and the
solution was a ring voltage booster t bring it up to 90V sinewave instead of
about 50V square wave like some cheap ATAs put out.
In your case, maybe Mitel is being fussy about how much loop current it can
draw when it is off hook (might actually have a relay instead of a solid
state detection circuit).
http://www.sandman.com/loopcur.html
http://www.sandman.com/longloop.html
http://phoneman.com/loop-current-booster-plus.html
http://www.adamtelco.com/viking-tbb-1b-talk-battery-booster.html
In theory, the line should be capable of something like 24 mA of loop
current, most modern electronic stuff is happy with 10 mA.
You should be able to just short out tip & ring from the ATA with a current
meter to measure the loop current.
Cisco SPA122 spec sheet says 48V and 18-25 mA which should be fine, maybe
check the Grandstream spec sheet and see what it says. If you are getting
20 mA or close off-hook, and 48V on-hook, I'd call BS on the Mitel guy.
The Cisco ATA does have an FXS power limit that can be set from 1 to 8 REN,
but that's for ringing.
-----Original Message-----
From: Nate Burke
Sent: Tuesday, February 17, 2015 5:24 PM
To: Animal Farm
Subject: [AFMUG] OT: Types of Telephone lines
I'm trying to hook an ATA (Grandstream GXW4004) up to a Mitel PBX. The
Mitel is expecting a 'Loop Start' line. I've read through the Wikipedia
pages, and looked through the documentation. But I'm still confused.
How do you tell if an ATA is producing lines that are 'Loop Start' or
'Ground Start' Or is there something else it's doing.
The client is having issues where some calls are terminating in the
middle of a conversation, or not disconnecting and leaving the line
open. The PBX Contractor (the only way you can do anything with a Mitel
PBX is through a Contractor) is telling them that they can make no
adjustments to the analog card in the Mitel, and it's not working
because our lines are 'Not up to industry standards for loop start
lines.' When they had ILEC POTS lines, the PBX was working normally,
this just happened when we switched them to an ATA.
I have a ticket open with Grandstream, but I thought I'd ask here. Is
there a way to test loop vs Ground start, and verify that the ATA is up
to 'Industry standards'? The Contractor is Telling the client that our
lines have low voltage, and there is "data" present on the line. I
wasn't on site when the tech was, so I have no idea what sort of testing
he was doing.
Any telephone guys care to offer insight?
Thanks,
Nate
