I've been trying to get up to speed on telephony basics. In particular as it relates to the equipment my company is currently using. Our main system is an old SX200 analogue (the microwave looking one). I haven't really found a lot of good info on the workings and functions of the various cards and options for these models so I'm muddling through the best I can.

One of the resources I've found is Lee Goeller's website which, at least IMO, is a great resource. Especially if you want to start from the beginning and not jump right in with the current state of the art equipment, but want to learn how we got to that point.

After reading Lee's "The PBX: What It Is, How It Works." series, I've really learned a lot, especially stuff that's relevant to our old SX200 and antiquated telco.

Reading about outgoing CO and Tie calls got me wondering about something. In general (and in particular on the SX200), does an LS/GS card work in either Loop Start or Ground Start mode, or does that also mean that they can operate in both modes? What I mean is, does the card work in one mode for incoming calls and the other for outgoing? Is there some other hybrid mode or combination of LS/GS or is it always one or the other?

The reason I came up with this question is that I've been testing intercepting calls from our SX200 before they hit the CO.
Running in KewlStart mode, the channel bank answers the SX200 just fine, and can route those calls over VoIP channels beautifully. However, if they are local calls and I try and dial out on the CO lines to pass them through, I lose the first digit dialled and the line seems to hang. This seems to fit with the description of the problems that Ground Start is intended to solve. I intend to try switching the FXO ports to GS mode and see if that makes a difference, but I wanted to hear what the experts say about this, and if anyone knew of some sort of hybrid LS/GS operation.

My other thought was that the SX200 was detecting the mode (KewlStart) of the channel bank and adjusting itself to it.
This would also explain why one side of this setup works and not the other.

Anyway, I'll keep reading and testing and hopefully figure it out. I was just really interested in hearing from anyone that had any thoughts on this. So far I'm finding my telephony crash course tough, challenging, and very interesting. It's a totally different world from I.T. and is pushing my old brain to think differently. I'm sure this is a good thing. ;')

On each CO trunk card, there is a LS/GS set of pins to choose which type.

The trunks need to be configured the same on both sides, PBX and Channel Bank, to work properly. Is there a problem with the current operation?

On the old 200 analog there are actually slide switches that dictate whether the circuit on the card is treated as loop or ground. Loop or ground does not really affect inbound (as far as being able to ring the PBX) it does however affect whether or not the PBx can seize dial tone when trying to originate a call. If you have a GS trunk and the card circuit is set to loop (or vice-versa) you will not be able to pull dial tone on the trunk from the CO and the outbound caller will receive dead air.


The SX 200 cannot automatically "detect" anything. If you have a switch on a CO card set to GS then the PBX will try to apply ground to the trunk (if you do not have a good ground to the PBX it will fail to pull dial tone). If the circuit is set to loop start it will just act like your phone at home and come off hook to pull dial tone.

Since your your Mitel seems to be having problems, and since it was most likely installed originally with G/S trunks, you'll probably need to pull the trunk cards and set them to L/S. It's really not hard to do, IF you have the book, and know which ones need to be changed! The one that shows the trunk cards, 3 different models, 111, most often seen 211, and seldom seen 311. They have line drawings of the cards with switch call-outs. Oh, this part you'll like. Any card with BLACK pulls can be removed when the system is running. Mitel says it's ok, it won't hurt the system. It MAY knock down a call in progress, but heck with 'em if they can't take a joke. DON'T PULL ANY OTHER CARDS WHILE THE SYSTEM IS ON!!!!! John C.

lightninghorse... Yeah, the telco guy told me that before, we had a problem with a trunk and he told me to go pull the card and put it back in to reset it without having to reset the whole system. I asked twice if he was sure since I couldn't believe it. ;')

Where can I find the info on these cards and the switch settings?

However, for this problem, I'm not having trouble with the Mitel. It's talking to the channel bank nicely. It's the CO lines that the Mitel _was_ talking to that I'm having trouble with.
Now that I know that there's no hybrid mode or autodetect on the LS/GS cards, I'm wondering what the issue is getting calls out on the CO lines. I'm not too worried yet as I haven't really done any testing or monkeying with this yet. I just wanted to get some background before I started that process.
Now that I am fairly sure the CO lines aren't setup GS (since the Mitel that was talking to them talks fine to my channel bank which is configured for KewlStart, which is essentially LS) I'm now thinking I just need to run FXO tune to get my channel bank's FXO ports matched to my CO lines. I'm using an Astribank XR0010 BTW. It's connected to an Asterisk box. The whole purpose is to sit between the Mitel PBX and the CO Dial Out lines and intercept long distance calls and route them out VoIP. This part works great BTW. The second part is to route local calls out the FXO ports to the CO lines.

The Astribank is able to talk to our other standard B1 lines just fine using KewlStart so I'm thinking I'm missing something with regards to setting up the CO/DO lines.

Thanks for all the good feedback.

Oh, BTW, our LS/GS cards are 9109-011-001-SA models.
I'm not sure how this relates to the 111/211/311 numbers that Lightninghorse mentioned.

I'd love to know a source for documentation on these and the SX200 in general. I've been all through the net and Mitel's site and found a few things. But none of the detailed stuff I'd like to see. The kind of manuals a tech would use to set these up.

This is frustrating because I was able to download every kind of manual and spec you could imagine for our little Nortel at one of our other buildings.

The 9109-011-001-SA is a analog trunk card for the sx200 digatal sx200light sx 200 el/ml & can be used with the sx200icp pbxs

As TDS pointed out, your trunk card indicates a "Digital" system. With Jumpers, not switches. Not sure where I drew the conclusion you had an old analog SX200. Does it run on 5 1/4 or 3 1/2 floppies. Either in a cabinet resembling a clothes washer, or multiple cabinets resembling computer towers. Or does it have a flash card, with cabinets that resemble Microwaves? John C.

Since he's calling it a refridgerator model, it has to be a digital or combo. The card part is definitely a digital though.

OK, well it has a main bay and an expansion bay.
Both have white front covers and I suppose the closest appliance would be a microwave. So it looks like two white microwaves.

As for storage, the main bay has a card in a slot next to the PSU which has a memory card sticking out of it that looks like a PCMCIA flash drive. It may not be PCMCIA, but the form factor is pretty close. The Flash card is labelled SX200 LWN (at least that's what I think it says, it's hard to read the card as most of it's behind the smoked plastic front of the card and the letters LWN are in a silly stylized font that runs the W and the N together.

I was always told it was an analog system. Though it has digital phones I didn't think this was related. My understanding was that digital referred to the ability to interface with digital trunks like ISDN etc.

Nothing is labeled on the system itself and there are no real manuals with it. Just for the console and basic voice mail operation etc.

So I've been looking through different documents and it seems like we have 1 SX-200 ELx cabinet and 1 peripheral cabinet (which looks identical to the main cabinet, but with less connectors on the back).

Sorry for the confusion and newbie mistakes, but I've been thrown in the deep end on this project. I'm doing my best to learn what I need to know but the curve is steep and sometimes being an IT guy works against you as it predisposes you to make assumptions about how something works that might not be true.

Ok, you have the ML/EL series. T1 is usable with one PCB that goes in slot 10 or 11, 5 or 6 must be empty. Depending on what release of software you have, ISDN is also possible. I think johnp can address that much better than I, never have installed an ISDN on a Mitel. john? John C.

Well, since we are all analogue here, I've already gone that route. I'm actually not having any trouble with the Mitel yet. But talking to the telco trunks is flaky. Once I get all my lines wired, I'm going to run the line impedance matching on all the lines and hopefully that will sort it out.

While I'm finding out all about our Mitel, is there any way to tell what type of signalling option our DID lines are using by looking at the Mitel DID cards?

What I mean is, we have analogue DID, but I don't know if our telco uses wink start or what to signal the PBX with the DID extension.

Anyway, thanks for all the great feedback and help.

I'll have to do some time in the computer forums and try and contribute back.

BTW, the card that has the Flash card in it is labeled
MCCIII-ML STRATUM 4 9109-610-001-NA

The way to tell how the DID is setup is by viewing the programming forms 13 and 15. If you don't have access, another method would be to use a butt set with a polarity light attached to the circuit. If when going off-hook on the butt set, the polarity light comes on for a second and goes off. Then you are set for wink. If the light stays off then it's likely immediate start. If the light stays on all the time, you leads are reversed, immediate start. I'll let you figure out what happens if the leads are reversed and it's set for wink.

John

Trying to cram all this telco knowledge hurts my Medula oblongada. ;')

Now you know how we feel, and a lot of us have been feeling that way for years Seems that either the Mitel is toning out before your box is ready, or your box is toning out before the co is.

To verify where the problem is, connect a test set on the input to your box and dial a local number. If it fails, your box is likely the problem. I find it hard to believe that the Mitel isn't providing all digits. You may need a pause before dialing, I've had to do that on some 3300's when they dialed before the co was ready.

johnp,

I'm pretty certain there's nothing wrong with the Mitel. My box gets and interprets the tones from the Mitel just fine. I can even see in the logs where it picks up, and interprets the correct numbers from the tones. It's when the box tries to dial out on the CO lines where I'm having trouble.

Hopefully this week I'll get my connectors in (back ordered)and get all my cables built and I'll be able to run impedance matching on all the lines and get it sorted out with that.

If that doesn't do, I'll try some other ideas.

Thanks.

My approach would have been to connect to the voip unit via T1 and change the routing in the Mitel to use a list for LD dialing, with first choice thru voip, then via local pots. I would have only setup enough channels on the T1 tie that the voip box could handle.

Kind of a kiss approach, but it's scalable.

Yes, well I thought of that too, but we have no assistance for Mitel programming or hw changes.
Our telco has no interest in helping us give them less money.
Also, paying them to come setup and configure that setup would have cost enough the the VoIP would have taken a good long time to recover the cost.
We are really only looking at this as a intermediate step anyway as eventually we will replace the Mitel entirely with Asterisk and IP phones so there's no point in buying any hardware or programming that we won't be keeping.
Given we have no real digital service options here and will be on analogue CO lines for the foreseeable future, this setup made the most sense to me.

T1-DEA service here is $2500 a month with a $2600 setup fee. It's just not worth replacing our current B1 analogue lines with this given our call load. Especially since VoIP will reduce our actually outside line usage dramatically.

I wish there had been a simple solution to this. If all PBX's (or better yet, telco interfaces too)had an Ethernet port and supported a web setup interface and g.729 it would be a wonderful world....

Just remember that back in the mid-90's, when your ML processor came out, it was the greatest thing in the world!!!
All of us phone 'veterans' will assume that since the Mitel pbx has been running solidly over the the years, it was never considered for upgrade or replacement (to the newer versions that do have ethernet/web support). Wish my PC from the mid 90's ran that long!!

If you want to have ethernet access to mitel pbx
200 digatal el etc. put a ipocket on the maint port use local ip address for in house or pulbic
ip for www access. then telnet into the system.

You might consider asking for an on-sight tech further down in the appropriate thread, or check for nearby techs up at the top of the page. They don't care one way or the other if your local telco loses revenue. John C.

Lightninghorse, Check my location. Unfortunately, no local independent techs. They all work for the local telco. My guess is that the nearest independent is 11 hours south in Edmonton.
There's essentially a telco monopoly here in the NT. It causes things like high prices and failure to be customer driven in their solutions and offerings.

fifty5footer:
I have no complaints about the Mitel. It's been a good system, and everything I've read seems to confirm that it's a reliable workhorse.

The main issue is that the telco is dropping maintenance on it. They'll no longer support it in a couple years and repairs now are straight labour plus parts.

I figured if I'm going to end up supporting the phone system myself, I might as well go to something I can better work on and understand.
Coming from an IT background and being a pretty fair UNIX/Linux admin, Asterisk made a lot of sense.
Plus, Asterisk is widely supported, and there's even good paid support options available. Also it seems very flexible and highly resistant to obsolescence. We can just keep upgrading or replacing whatever component we need to with no worries about vendor lock-in or dead upgrade path.
And these days, you even have to worry about your vendor going out of business and losing support/parts. How would you like to have been responsible for installing an expensive Nortel system last year and now have a freaking out customer?

Anyway, thanks for all the valuable feedback everyone. I certainly appreciate it.

Coming in late here but...
Looks like you have a 200 EL.
If you have the right kind of handsets (no 400 series) you can upgrade to a 3300ICP.
This will give you:
web interface
sip trunks
sip softphones
sip hard phones
teleworking
etc/more
All of this and more while still using the sets and most of the hardware you already own!