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BT ISDN30 vs ISDN30e in contact-centres

Can a WS-X6608-E1 line card for the Cat6500 support British Telecom's ISDN30 with DASS2 signalling? (as opposed to ISDN30e which has I.421)

The reason I am asking is because BT say that only DASS2 supports the ability to dedicate a fixed number of channels to a specific phone number.

ISDN30e apparently cannot - if 10 numbers are configured on 180 ISDN30e channels, calls to one of the numbers can take up all 180 channels... i.e. in a contact-centre environment, numbers of calls cannot be limited out in the PSTN. The customer switch must track the numbers of inbound calls to a specific number and then divert or offer busy tone, etc...

I understand that Call Manager cannot track the numbers of inbound calls coming in on a specific number and limit them. Is this true?


1. Use BT ISDN30 / DASS2. Partition the 180 channels to dedicate specific channels to each of 10 inbound calling numbers. Problem - can 6608 cards support this?

2. Use BT ISDN30e / I.421. Unable to partition 180 channels to specific numbers. All inbound calls are in a free-for-all competition as to who gets in (on any channel). Problem - can CallManager track numbers of inbound calls?

Any ideas gratefully accepted!

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Re: BT ISDN30 vs ISDN30e in contact-centres


6608 does not support DASS2 as it's a special UK signaling protocol developed by BT so you have only option 2 , there might be something you can do on the application's side to limit the calls. Will you use ICD/IPCC for the call centre?

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Re: BT ISDN30 vs ISDN30e in contact-centres

Yes, IPCC will be used for the call-centre part - it will have 2 x ICM, 2 x CTI and 2 x IVR servers....

I would envisage that the number of inbound calls would be physically gated by the number of agents - in this case around 80. So out of 180 channels, only 80 could be taken by IPCC agents. I would imagine that ICM could count inbound calls as well? This would always leave 100 lines free for the main number for the 500 ordinary staff who work in the building also i.e. the call-centre would not encroach on the main line.

However, how do you stop the main line encroaching on the call-centre lines? e.g. if 180 people decide to call staff (non-agents), then how do you limit them so the call-centre ALWAYS has 80 inbound lines dedicated to it?


Re: BT ISDN30 vs ISDN30e in contact-centres

Hope someone can suggest something better but i see only this way for you with 6608..

You can dedicate 3 PRI links to the callcentre and 3 links for regulars calls.(90 /90 instead of 80/100) .Then i guess you will need at least 2 PRI ports on 6608 for the IVR (well hope its IP IVR and not our IBM DT6000 as you will need more ports because of the tromboning...) and you still need 1-2 ports for it's more than one 6608 blade anyway

Regarding limiting the number of calls by the number of agents..You will always have calls in queue on IVR and some calls may go to the IVR only without coming back to the agent so it's pointless to gate it that way and if you are planning to have 80 agents you need much more channels.


Re: BT ISDN30 vs ISDN30e in contact-centres

Of course the problem with having the ICM limit the number of incoming calls is that the call has to be presented to the system first before it can be rejected therefore taking up a channel (albeit for a very short time). With DASS II this was not a problem as the exchange limited the number of calls without presenting them to the switch.

You could try using the IQ200 interchange unit from Westell to convert the DASS to Q.931 and stick with the DASS circuits (