sundance-communications.com/forum Forums TDM Business Telephone Systems Inter-Tel Telephones & Systems Capacity

How do you calculate how many calls your switch can handle. I am trying to figure out how many calls we can have incoming, on hold and outgoing. I am trying to plan for the future and trying to determine if and how many additional T1s we will need.

Well, how many trunks does system currently support? You get one call per trunk.

I have 8 Loop Start and 46 B-Channel. I am guessing that means I can support 46 calls.

Your system processor will limit the number of 'devices' that will be supported. You may have a 64, 128, 256, or 512 CPU, CPC, or CPS and that is the total number of all telephones digital and analog, CO lines, T1 channels, etc that your system can handle.

Count up your devices for future planning - having to purchase a processor for a T1 upgrade is NOT a pleasant surprise!

As to actual call handling within your system, 4 lines per LSC, 4 per Daughter piggyback card, and however many channels you have enabled on your T1. You can go to Trunk Groups to do a count, just don't include the trunks under PP011/Unused CO Trunks.

If you've got 12 CO lines, you can get 12 calls in/out/or on hold - nevermind how the telephone is designated, the calls will stack up. 4 Co's and 23 B-channels from a T, you've got the ability for 27 calls.

Hope this info helps.

I must be miscalculating somehow. We have had as many as 42 calls on hold with more than 15 people on active phone calls. It does not seem like this should be possible based on the previous post.

Well, you replied that you have 46 B-channels and 8 loop-start trunks. That adds up to 54 trunks if indeed all loop-starts are connected to dialtone.

If you seem to have more calls in progress than you have trunks, then:

1. You have mis-calculated how many trunks you have and/or,

2. You are monitoring both internal and external call activity in CCS.

Please excuse the pea-brain question but I'm a Network/Sys Admin with no prior background in phone systems...

I'm trying to understand what I've got, how the port counts work, and how much head room is available on our current Axxess system (9.006).

For sanity sake I'll go over what I've got and perhaps someone can enlighten me on my current count? Equipment is as follows:

* (1) 550.0121 Power Supply
* (1) 550.2255 16+ DKSC (16/16 in use)
* (1) 550.2101 8 Port SLC (4/8 in use)
* (1) 550.2300 LSC (unused, to be removed)
* (1) xxx.xxxx T1/E1 (6 B-channels total)
* (1) 550.5040 EVMC (14/32 in use)
* (1) 550.2030 64 Port CPC/CPU

From what I've been told, it's active ports that count against my 64 available ports, right? That being said, my count leads me to believe that I'm using (in order from above) 16+4+6+4 = 30 ports. Is there anything that I may be overlooking? Does that appear to be a correct count? I'm happy to provide any additional info.

Also, regarding the LSC, I presume it's not in use as there is no ribbon/cable attached to the card. It's just sitting in the cabinet. In my ignorance, I don't understand why I'd need this <enter laughter> with my current setup.

I greatly appreciate any info provided!!!!

Thanks,
Chris

Looks like when you remove the LSC, you'll have 2 open card slots. On the EVMC, you don't count mailboxes, but ports. EVMC's come in 4 and 8 port flavors. For now, since you have the 32 mailbox EVMC, I thnk it is safe to assume you have the 4 port EVMC. Also, on the T1 you have 6 B channels which means it is PRI and would require a D channel for signalling. That brings the T1 port count to 7. 16+4+7+4=31 ports. (You may also be using up an additional port if you are using an external MOH source)

Thanks Tellink. I appreciate your insight.

Not trying to be contentious here but removing the LSC will give me (3) open slots, unless I'm missing something. Currently I've got (2) open. Am I overlooking something?

I didn't figure in the D channel because I didn't see it in the phone system programming. Had you not pointed that out as a port count, I would have forever been one off in my count - thank you. Is that just an 'unspoken' port count or is it actually set somewhere in the system programming? Sorry if that's a silly question. I just like to know as much as I can.

You're spot on in your (4) port EVMC flavor assessment. I should have mentioned that in the original post.

Regarding the external MOH, by external that means a device/source that's not in my cabinet, right? Another silly question I'm sure. I'm trying to make sure that it isn't an add-on that could be configured within the EVMC.

A bit off topic; I presume that I can add another 16+ port DKSC and be fine with my current 4A power source? Is that a safe conclusion to arrive at? The LSC will be removed prior to the 16+ DKSC addition.

Again, I greatly appreciate your time and insight.

-Chris

Nevermind on the MOH question. It'd still be cool to know if that could be a function of the EVMC; however, my sys programming indicates that the MOH is on the CPC/CPU board. Dur!

Thanks again to all that contribute to my phone system understanding!!! Including all whom have posted to this entire forum. You guys are great.

-Chris