Most Mitel PBX's use D4/B8ZS. It's a strange setup but a known Mitel configugation. Their vendor is yanking your chain. From: voiceops-bounces at voiceops.org [mailto:voiceops-bounces at voiceops.org] On Behalf Of Richey Sent: Thursday, December 02, 2010 9:26 AM To: voiceops at voiceops.org Subject: [VoiceOps] Probably OT - Mitel - Adtran Sorry if this is off topic but I really don't know of a better place to ask this question. I had a customer with a couple of locations that have Mitel SX200 PBXs. Their voice vendor asked us to hand them a Voice T1 out of our CPE which is an Adtran TA904. They told us that the T1 needed to be configured as D4/AMI. After the install the customer experienced dropped calls and the vendor could only really say that everything worked find with the previous carrier so it has to be our problem. After a day or so of trying to figure out the problem I switched to D4/B8ZS because I was out of ideas. As soon as I switched to D4/B8ZS the errors stopped and the calls stopped dropping. I questioned the vendor again and he swears that their side is set for D4/AMI and now he thinks it much be a glitch in the Adtran. I think it's either the vendor didn't look at the config or it's something strange in the Mitel. Has anyone else come across this before? Richey

On 12/2/10 6:25 AM, Richey wrote:

Sorry if this is off topic but I really don?t know of a better place to ask this question.

Works for me. It is operational, voice related.

I had a customer with a couple of locations that have Mitel SX200 PBXs. Their voice vendor asked us to hand them a Voice T1 out of our CPE which is an Adtran TA904. They told us that the T1 needed to be configured as D4/AMI. After the install the customer experienced dropped calls and the vendor could only really say that everything worked find with the previous carrier so it has to be our problem.

Isn't that always the case? Especially when connecting to hardware best described as "quaint"?

After a day or so of trying to figure out the problem I switched to D4/B8ZS because I was out of ideas. As soon as I switched to D4/B8ZS the errors stopped and the calls stopped dropping. I questioned the vendor again and he swears that their side is set for D4/AMI and now he thinks it much be a glitch in the Adtran.

We have done the same thing, and it works either as D4/AMI or D4/B8ZS as long as it matches the configuration in the Mitel. The SX200 is likely indeed configured for B8ZS. If you're not seeing incrementing errors you're probably OK. There's nothing technically wrong with D4/B8ZS (or ESF/AMI) it just isn't usual to see it as it usually makes no sense.

I think it?s either the vendor didn?t look at the config or it?s something strange in the Mitel. Has anyone else come across this before?

Programming the Mitel SX200 is not intuitive. I actually got certified in it decades ago but it's been a long time since I've touched one. There are different "Forms" that are like menus. If I recall correctly T1 framing and T1 line coding are on different forms. They may not even call it "B8ZS" but something else. Getting clocking right can be fun as well. -- Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net Impulse Internet Service - http://www.impulse.net/ Your local telephone and internet company - 805 884-6323 - WB6RDV