sundance-communications.com/forum Forums General General Telephone & Systems Information DID Numbers - T1 vs POTS lines

We are looking at putting in a VoIP system of some sort, most likely Astericks. And I have a question about whether or not one can use DIDs on POTS lines.

Background info: We currently have about 150 analog POTS lines connected to ~175 phones. And we are looking at needing 20 lines going into some box, either analog (POTS) or digital T1, to support VoIP sip phones or softphones on PCs.

I understand the Digital T1 would give us 24 lines and I can have any number of DIDs associated w/ the trunk to allow people to keep a direct number if they want. And as long as there is free channel the call will go through. But since the cost of the T1 is so high compared to 24 POTS lines, is it possible to have the Telco office (Verizon - centrex) use some form of hunt group that can work with DID numbers ? Am I missing something ?


Thanks

-rick

You have 150 POTS lines! Yikes. I would convert everything to PRI. Lets run the numbers; you have 150 lines * at least $20 a month, mabye $50 depending on the LEC. That brings you to somewhere between $3000 and $7500 per month, without even making a phone call. A PRI will run you $500 to $1000 per month. Big savings there.

A T1 will support 24 calls at once, 23 if you use PRI as you need one channel for a D channel. Now you can have as many DID's on the T1 or PRI as you want. Need 200 DID's, then buy 200, the number doesn't matter, but just keep in mind that you can only have 24 or 23 calls at the same time.

I would never use a system like Asterick for a business soultion, because it's not a business solution. What you should do is consult a qualified telecom company to supply you with a quote for a real business class solution. The Return On Investment on a new system would probably be less than one year seeing that you have 150 POTS lines.

FEC-III
Please fill in the blanks on your profile . What system are you using that can support almost the same number of analog trunks as analog phones ? 2 PRI'S would meet your needs ! If your business depends on the phones to keep the doors open , choose wisely not cheaply ! My 2 cents .

I'll echo the sentiment, don't go with an Asterisk system. If you have that many phones, they are obviously important to your business. Get bids from several professionals, not someone who doesn't do this for a living.

With a PRI or a T1, you don't need a channel for every number. The telco sends a signal to your equipment that tells it which DID is being called.

Good luck!

Ditto on all of the above but to answer your question yes you can have DID on a POTS line but it incoming line only plus just like the PRI one call per line

Just for the record, Asterisk has a 99 cent version and a higher end more stable professional version that CLECs are using for VOIP.

If FEC-III wanted to explain his current setup and what he is trying to accomplish, we would not be so much in the dark.

If these people had heavy phone usage in or out, you couldn't cut down much on usage. If he had a reading on how many minutes a month was being used, then there would be a starting point.

Some basics:

Analog outbound DID's are not POTS lines, they have no battery or dialtone. They are essentially dry lines connected to a hunt group at the CO. Battery and supervision is provided by a PBX or a standalone DID unit.

I have heard some phone men express amazement that they are still out there, but they are, even though both way DID service on T1 (Flexpath?) is now more common.

Original Poster, you are bleeding on the floor thru all of those phone lines and a nice small-to-midsize PBX will fill the bill quite nicely for you. Anyone here will happily recommend their favorite system and any reputable dealer like those to be found here will help you analyze your traffic flow and design a system that will pay for itself in a surprisingly short time compared to your costs now.

And, because I'm a Telecom Fundamentalist, I suggest not rushing into VoIP, just because you heard it's the latest and greatest or whatever. Current TDM technology used in traditional PBXes is mature, solid, reliable, and very feature-rich. But that's just *my* humble opinion.

jsaxe

Rick

Please fill in your profile. I think the people here can give some valuable insight into saving $1,000.00's of dollars and hopefully you can make an informed decision about what is right for your business and your budget.

I have a T1 card in my system which allows my phone system to used the trunks like stem cells.

I can make the system route the call to any extension I want just by the number dialed or use the trunk or outbound calls.

I have a SLI card in my system that allows me to attach fax machines and other analog devices to my phone system.

Bottom line is that if you configure your system right, you can use 1 PRI(23 trunks) more effectively than 80 POTS line which would normally be dedicated to fax machines and private phone in offices, etc....

I'm not good at explaining but basically I use to have 84 trunks and after I got my sytem configured right, I now just have 23 trunks which can handel the same traffic without any busy signals before of more efficient system.

Thanks.

jsaxe did a great job explaining the 'DID's over POTS'. We have a couple of customers that can't get PRI but have the 'DID on POTS'. It works once it is set up correctly, but getting the setup working with the local CO was something I'd rather not repeat (and yes, they called on their OLD techs). If the PRI or T1 is an option, go that way. Good luck.