HiPath 4000 & ISDN30e....

[n2ckb]

Hi all,

My expertise is IT, but in my new job I also manage our communications systems. I don't support the system, as this is subcontracted out.

I've recently reviewed what we are paying for our telephony, and am surprised that our system uses 30 ISDN30e lines, as we only have around 100 DDIs in the office (of which 25% are unused). With some research, I have found that these lines are able to handle potentially 30 simultaneous voice calls. Does that therefore mean that 30 lines equates to the potential of 900 simultaneous calls?

Do we have far too many lines? We do not use the lines for anything else other than voice calls.

As mentioned, I am new to the world of telephony, so please be gentle! Any advice would be gratefully received.

 

[donb01]

I don't know how much you are paying for those lines, but in our market a single ISDN PRI line which can handle 23 simultaneous calls runs $500 - $600 per month. You might be able to save some cash by switching. You would need an open port on a T1 card in your system and a CSU/DSU to interface the line, and possibly and ISDN PRI license for the switch if you don't already have it, but those are one-time costs and you could potentially save a bundle.

I use 1 ISDN PRI line at two of our sites that support over 200 people and never have any issues with trunk blocking (busy signals for customers, or unable to place calls for employees). I will add though that I also have a voice WAN where a T1 connects each site to our main location, and all internal 4-digit extension calls from building to building are routed over that rather than the outside lines, and this does save a lot of call volume.

At my main site, 3 ISDN PRI lines (69 channels) support incoming and outgoing calls for over 1200 devices.

You might want to look into your options.

 

[Iamnothere]

That just sounds CrAzY! Are you sure the trunk circuits are not BRI (only 2 B-channels per circuit)???

 

[n2ckb]

Thanks for the feedback guys...

My ignorance of the setup meant that I got the wrong end of the stick. We have 30 channels on one line, which is way different to my thought that we had 30 lines of 30 channels.

I guess the question is whether 30 channels, allowing 30 simultaneous voicecalls, is excessive for only 50 employees being in the office any any one time.

I've extracted the call data from our HiPath system and worked out that our maximum outbound concurrency was 6 calls. Bearing that in mind, I think we could quite happily halve our channels from 30 down to between 10 and 15. That will save us a fair amount of money.

Thanks as always...

 

[donb01]

Well, if I use MY math for your situation, and leaving some room for growth, let's assume you have 9 lines outgoing and 6 DID lines coming in. Typically the ratio for DID lines is 1 line for each block of 20 numbers, but I have far exceeded the numbers to lines ratio with mine.

So you have 9 trunk lines at $35/mo each = $315
and you have 6 DID lines at $60/mo each = $360.

That does not include tax, title, and license.....

So if your current line is costing you less than $675 a month then you are saving money the way you are now. This also does not include charges for the outgoing calls.

This is how I cost justified my $550 ISDN PRI line with 23 channels - it was cheaper than the lines it replaced, plus instead of paying 15 cents (or some other discounted rate) per outbound call I pay 0.08 cents per minute. That means that any call that is shorter than about 18 minutes saves me money and anything longer than that costs me money. Back when I did this math the national average length of call was 3.5 minutes, and I was saving thousands of dollars a month in call costs. This has all since been handed off to someone else and I've ceased paying attention to it, but I know we're still saving money.

So there's another consideration of whether you need to change up your service or not!