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Business Case: Key vs Centrex

Business Case: Key vs Centrex

Business Case: Key vs Centrex

Researching pros and cons between traditional key system and lec/ixc centrex service.   

Company has hundreds of locations around the U.S. with an average of 10-20 users per site.  Using 5-10 lines per site.
There is not a need to connect the sites to the Main office as of yet but there may be one in the future.  Currently all locations have key systems from almost every type of manufacturer.  Company would like to standardize on one system or one technology. Please let me know if you require some more details. Any and all ideas appreciated.


RE: Business Case: Key vs Centrex

i don't see a need for centrex, for future connectivity back to the main office, you may not even need to replace the phone system, there are VoIP adapter units that sit between the phone system and the IP network that leads back to the main office.  However, do you have alot of calls back to the main office, how about calls to other offices.  

To replace these systems is expensive, you could look at a CLEC who could provide a local T1 with split voice and frame relay (assuming you have data going back to some headquarters).  

To sum it up, your solution may be the equipment but could also be the service. centrex, however, won't really give you anything useful.


RE: Business Case: Key vs Centrex

 Centrex most definately can help here.  If you have a servicer savvy enough, they can program the centrex features into the KSUs so you can transfer calls as if they were in-system at ANY location.  This would alliviate the cost of replacing any equipment as most (even old) key systems allow you to program the feature buttons.
 Of course, that's a lot of money to pay those servicers, too

   "The reward of patience is patience"
      -St. Augustine

RE: Business Case: Key vs Centrex

Problem with a centrex solution is in most cases when you want to connect two centrex systems together you have to set up a path between the centrex office locations, this normally costs the same as a DS0 data line and in a case of multiple locations you would have to have a network of paths (each path can take only one conversation at a time) This would be very messy as well as now you would be talking about getting different telco's to set-up one network. (no thanks) the VOIP onto a intra net or internet makes more sense, set up these VOIP ports to be incoming lines on each phone system and you have the rudiments of a phone network in place.

Communications Systems Int'l

RE: Business Case: Key vs Centrex

   Learn something new every day.  My interlata centrex expertise is non-extistant.
   Under those conditions, you are quite correct.
   Have you found Voip solutions cross-country to be as fast as tradional switching methods?  Going overseas with a Voip solution is tricky, at best, but have heard nothing regarding cross-country.

   "The reward of patience is patience"
      -St. Augustine

RE: Business Case: Key vs Centrex

Thanks for everyone's post thus far but I would like to step away from the networking/voip portion of this discussion and focus mainly on the features and functionality of both solutions as stand alone products.  I was mostly looking for reasons why a business would choose one over the other, keeping in mind that we are talking about multiple locations.

Thanks again for everyone's post.


RE: Business Case: Key vs Centrex

 It is the multiple locations at the end of your quirey that sparked the variety of responses for/against VOIP.
 Centrex was first developed by the Telcos to provide useers with a phone system before good PBX and Key systems were available any but the biggest of organizations.
 Centrex is really just a centralized PBX and today offers centralized voice mail. There is little difference over a Key system with or without DIDs.
 The equipment costs for centrex can be the same as a Key system depending where you buy them.
 For an organization as you described above the key issues are dependability, and servicing. You don't want the equipment to stop working, and you want a huge choice of vendors who will arrive with the skills and parts required to fix problems.
 So... my choice would be BCM or Norstar Key Systems.
 1. Parts are available from the equator to the arctic
 2. service personel are equally available as more service
    techs know Norstar than any other one product;
 3. interchangable parts have been made for Norstar since
    1989. This means that you can use a 1989 set on a 2003
    KSU and it will work, & vice-versa (some limmitations);
 4. Norstar has good remote service systems that allow back
    up and restore, remote programming, same for Norstar
    voice mail with NAMs able to do remote voice recording.
    BCM integrated Call Pilots also do remote voice overs;
 5. Norstar is dependable like a rock;
 6. is still in current production and R&D;
 7. you are not dependent on Ma Bell/Telcos for purchasing
    and maintenance - in short, you can shop around;
 8. you can migrate to the BCM VOIP platform without
    changing your telephone sets or Call Pilot voice mails;
 9. Centrex won't do integrated cordless anything.

Sorry for long post. But hope this directly answers your question from my point of view.


RE: Business Case: Key vs Centrex

 You mention in posts above of the VOIP adapter units for KSU trunk ports. I have been looking for these products and not found one that directly suits my research criteria. Wonder if you would mind posting the specific product you refer to?


RE: Business Case: Key vs Centrex

Thanks Jsaad.


RE: Business Case: Key vs Centrex

Hi ghost03,

There is one feature that CENTREX has that no one so far has mentioned and that is "DID-TO-DOD" call transfer. Since Centrex is CO based you don't have the transmission losses brought on by "end-of-loop" bridging in the previous mentioned systems. Even with some amplified bridges it still can't hold a candle to Centrex, because once the call is transfered you drop out and the line is free for more calls! When you bridge, the two lines are inuse for the entire call. Also, even if you used 3-way calling and put the call on hold, it ties up that line and if it is a hunt group you would need the 3-way feature on every line. With Centrex it is part of the service offering.

If this is something that is useful in your situation, you could transfer calls between offices or anywhere for that matter. If toll charges are a problem, you could use INWATS TOLL FREE numbers for the company and point them to the main  numbers. Then transfer the calls that way. Nowadays you can get some pretty good rates from some of the service providers for Toll FREE INWATS (ie: 800/888/877/866/855).

Just some food for thought!


RE: Business Case: Key vs Centrex

 In our area the hookflash 'external' transfer is a line option like CLID and voice mail. Turn it on, turn it off as you require. Obviously then having a formal Centrex is not necessarily then required. But good points for cost/routing and feature sets available.


RE: Business Case: Key vs Centrex


In applications I've done replacing Centrex is merely desired as "reduced reliance" where a networked multi-site organization wanted what equates to their own Central Office functionality. Centrex offers a great many helful networking features and a dialing plan locally - but this becomes interesting when dealing with different exchange carriers nationwide. Plus there is the cost as well. The rationale behind going to IP trunking to replace Centrex is to provide a lower recurring cost or to take advantage of an existing VPN or infrastructure that has been paid for. I still believe that there are some security issues involved with IP that do not exist over the PSTN as well. If the Centrex features are needed AND you are going to establish some sort of frame or VPN for your data connectivity anyway it makes good sense to explore networked switches/PBXes over IP or QSIG. If there is no plan to network your data then it does not make fiscal or reasonable sense to establish one strictly for voice. Data networking should lead to voice networking sharing that connectivity-not the other way around.

RE: Business Case: Key vs Centrex

Hey Ghost,

You have lots of good ideas here to kick around so I hope you don't mind if I muddy the water a little.

No one has yet mentioned the available NARS to you regarding Centrex service. NARS are Network Access Registers that allow "outside calls" meaning outside the Centrex network. You may want to check your phone bills 'cause 10 Lines does not always equal 10 NARS.

The other option I wanted to mention is dump that Centrex stuff. On site voice mails require a SMDI (Message Desk)link at a considerable cost, some down time, dedicated modems, etc. and off site voice mail is a per mailbox expense.

Look for some good fractional T-1/Frame Relay pricing as mentioned in other post.  With hundreds of sites, you can get real good pricing on SDN (System Defined Networks) that allow low cost calling to other facilities with your "defined Network." The first example to come to mind is also probably the largest around, is the US government on the FTS 2001 Network. Normal rates apply to non government calls and calls to other government facilities on the network are greatly reduced, sometimes FTS referred to as "Free Telephone Service" as it is so cheap. Also the other reason Worlcom/MCI will NOT go out of the business, the government would not be able to call LD.

Sorry for the long post but there are other options besides Centrex, Voice over Frame and Voice over IP.
Good Luck.

Jerry Pannell

RE: Business Case: Key vs Centrex

Ghost you really need to evaluate on a site by site basis.
There are a lot of pros and cons in all directions. If your locations are spread across the country you will deal with different service providers for each location. You need to look at the cost of a key system (or small pbx)and the cost of the lines to support it vs the cost of centrex lines to do the same thing. I have found that centrex for a small location can be more economical. I would think that you may find the same thing, but as the number of users gets larger a local system is more economical. I think you may find that the cross over point will be somewhere in the 15-25 user area. One other point to consider is maintenance, with centrex you don't have any.

RE: Business Case: Key vs Centrex

I agree with Arr except that Key systems offer more features, also it is a big headache for Head Office with so many different phone systems.
Get the same phone system at all sites with remote access and fully train the admin at H.O. to dial in and make changes.
Centrex cost's too much in the long run without the full features that key systems offer.

Norstar BCM or the new NEC IPK would be my suggestion so that you could utilize the internet and pay a decent price for the features and funtionality of these KSU's.

Far too many times have I seen H.O's pay too much money when all the sites have different setups/KSU's.

RE: Business Case: Key vs Centrex

May I suggest you step back from the technology for a moment and focus on the business reasons for which you need telephone service? Do your offices interact with each other, or are they autonomous? Do you need to forward voicemail messages? Do you require the ability to transfer calls between offices? Between office and headquarters? Do you want to route all your LD calls to a central location to take advantage of dedicated services? Do you need CDR? Do you have a maintenance organization that can accept, document and distribute help desk type calls? Do you want to do your own maintenance or call a vendor? Or do you want your individual offices to manage their own maintenance? And, what is the most important criteria - purchase cost or ongoing operation cost or ease of use or ease of maintenance? I think if you clearly articulate the features you want/need/would like to have, then vendors can propose the right solution, whether VOIP/Centrex or traditional key system, and you can evaluate based on which system best addresses the features you want. Again, the technology is second to providing the features your company needs to do business.

RE: Business Case: Key vs Centrex

So here's the question restated, Why not centrex?  The cost appears to be less if you need 20 lines and NARs or less.

RE: Business Case: Key vs Centrex

Being a Comdial authorized dealer, Capitol Communications, I have to ask, have you looked at the Comdial pruduct line. It has proven its reliability, scalibilty and its affordability. The FXII is an awesome system that can be networked together. Even their small business system, the DX-80 would be be an excellent solution for your communications needs. The DX-80 is coming out with a new VOIP gateway that is extremely affordable and will lower lond distance costs, especially between sites. The DX-80 has come a long way and has proven to be a very strong small business system at an affordable price. If you would like a better look at the system  go to www.comdial.com, then products, systems, DX80, then Dealer tesomonials. If you have sites in NJ or Philadelphia keep us in mind.

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