UC500 for a new installation. Requirements and question on SIP and B-ACD

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Jan 4th, 2008
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Our company (a local ISP) is willing to buy a UC520 bundle with 4 BRIs and 4 FXS for analog telephones and FAXes.

We plan on having 30 Cisco IP Phones. No teleworkers. Multiple SIP trunks and B-ACDs.

The idea is to start using 2 BRI to receive/send calls and faxes with our existing PSTN numbers. Next we'll buy a dozen of SIP numbers (every account/number has a different username/password but they're with the same provider) to realize a semi-keysystem where some SIP numbers are directly put to the phones. These phones have obviously internal numbers too and are 7906G.

Next, up to 10 outgoing calls must use an additional SIP trunk and the exceeding calls are to be routed to the ISDN BRIs if available. If needed, with a different prefix anyone may choose to be routed to the ISDN for the outgoing calls. This is a matter of precedence and destination patterns, right?

Now the toughest part for me.

When an incoming call to any of the BRIs or to a specific SIP number (obviously not one that is directly overlaid to phone button, but probably the one used to make outgoing calls) must be sent to a hunt group (likely parallel), if no one is answering in 20 seconds a B-ACD takes over putting the call on queue and continuing the parallel hunt. I'm not sure if this behaviour for the B-ACD is possible.

An analog FAX on a FXS must pickup the first free ISDN BRI line, so no intermediate tone of the PBX. I think it's called PLAR. Am I right?

Last thing. After hours anyone from any phone may enable another B-ACD that answers any incoming calls saying that the office is closed.

On the multiple SIP trunks I've found some resources that I cannot verify but seem to blend nicely with my specifications:



Can you help me? I'll share with you the final and intermediate stage of configuring this system, and as soon as my expertise grows I'll try to fit in this community :-) I currently hold the CCNA and working on the last 2 exams for CCNP.


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paolo bevilacqua Fri, 01/04/2008 - 09:39
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In general, all what you want to do is possible. Certain things will require specific confguration, and other will require understanding how the CME works before it can be bent to your will.

Example, the selection of BRI lines (via trunk-group), the B-ACD office closed, that in turn depedns how do you answer normally.

Again, the hunt-group that doesn't support paralle, so you need to use shared lines, or a bcast service like one that I wrote.

In summary, you need to start with the basic first, then get to the optimum, little by little. A lot also depends by user education, there are certain things that work in acertain way for very good reasons, but it can take some time before you educate the users on how to use them.

n.marcolongo Sat, 01/05/2008 - 15:46
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Thank you Paolo. The fact is that I can't recommend this solution if I can't be sure of the results. So it's frustrating to search and ask around about something I cannot try. Again, thank you.

paolo bevilacqua Sat, 01/05/2008 - 16:50
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So what will you recommend? I've installed many CME's in Italy and everyone is happy - they do things like call centers, multisite office, etc.

Some of them were using asterisk before, and have said they like CME better, it's faster, has more features and is better documented.

All problems have a solution, but if you never try you won't know. You can use a cheap old 17xx or 2600XM to see what CME does - really it's a lot.

n.marcolongo Sun, 01/06/2008 - 04:32
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I have tried with and old 3640 but the CME that runs on that it's not supporting the feature that allows username/password on a voice-port to have many SIP numbers. It hadn't a Unity Express so I was unable to try that either. Having seen the features on a UC500 I was trying to asses what you can do with an intermediate knowledge of the CME architecture. I cannot think to master TCL scripting to bend CME at my will in a couple of days. If you think it'll be appropriate I can post some doubts one by one an trying to understand which ones have to be confirmed and others that can go without a glitch instantly.

Thanks again for your help so far.

paolo bevilacqua Sun, 01/06/2008 - 04:39
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Sure, go ahead. You don't really need to mess with TCL for a nice CME setup. Beside, I already wrote the inflexible business hours for B-ACD/AA, and the blast hunt-group, that are popular requests. Both mods work nicely.

The SIP setup can be a bit of a problem, for example the username/password under voice-port in for incoming authentication, not outgoing!

But worry not, I have a solution for that too, at 1 cent a minute.

I'm always glad to help with CME, but in your case, beside the nationality, your last name matches a nick that I used in some occasions, funny coincidence :)

paolo bevilacqua Mon, 01/07/2008 - 13:31
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We also run an ITSP, in beta now. Official launch should be end of month. Will announce here :)


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