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Phones fail to pickup calls and phones swallow the first word after answering a call.


I recently replaced our old PBX with a brand new and shiny UC560.

The setup:

We have 4 SPA525G2 and about 14 7960s phones.

The UC560 is directly connected to a SG300-24p switch, which again connects two SG300-10p switches on other floors. The switches run, the UC560 runs the latest software pack (8.6). The UC560 is DHCP for the voice VLAN100 but does not provide any serviceces for the data VLAN1. We have an external firewall and router who do DHCP for the data-vlan. The WAN port on the UC560 is not used, firewall nat and VPN are disabled - the UC560 is "just a client" in our network. For what I can tell, the network configuration is working fine.

The landline are two German ISDN p-t-p lines connected to the built in BRI Ports. A 2 BRI VIC is also installed - it is configured as network emulation port and connects an ISDN-fax-machine (works also fine)

Most of the configuration was done with CCA just some special stuff (UCXSI, BRI as network emulation) was done by CLI.

The problems - maybe they are related, maybe not:

The first one is annoying but not critical: When I answer a call on my SPA525G2 I have to wait like 1-2sec (after moving the handset to my ear) before I can start talking, otherwise the caller won't hear what I said during those initial 1-2 sec. I did not yet verify the same behaviour on a 7960 phone.

The second problem is really critical. Sometimes (this happend at least thrice) when a call is ringing, after picking up the handest (or pressing the headset button, or pressing the speaker phone button) the phone will continue to ring and not answer the call. The call was a real call, because I called the caller back and asked if he just called, because I was unable to pickup the call. The problem might be blast group related, because at all times when it happed the calls in question arrived at a DID that is mapped to a blast group. After not being able to pickup the call on my phone, I jumped to a co-worker's desk and tried his phone, which is in the same blast group and I also was unable to answer the calls. This occurs on both SPA525g2s and 7960s and only occured with the blast group which contains about 15 phones/extensions.

Any suggestions to point me in the right direction are welcome!

regards + thanks,


Hall of Fame Master

Blast-group are notorious to cause all kind of trouble, even more for 15 phones, that is absolutely unreasonable.

Please, if you want to say that this is the way your customer wants to have, that's fine, I have heard that hundreds of times, unfortunately it doesn't change the fact that it is not the way for the system to work good.

Instead of racing for calls and ringing all across, configure a proper ephone-hunt with login-logout softkey, give people responsibility to answer calls in an orderly manner (think a small call center) and everything will work

If you really need to have phones ringing in paralle, use octo-line shared DN , not blast groups. You can learn about shared DN in the documentation.


Hello Paolo,

first thanks for your answer and quick response time.

This is why I chose a blast group:

Our security service calls the office if our alarm system is not engaged by 6 p.m. to see if the last person just had forgotten to activate the alarm system or if someone is working late. In order to accept this call the security service calls a distinct DID which should ring all phones in our office. Currently I solved this problem with a blast group (seemed perfect). This blast group is also used when our receptionists don't answer the main DID for 20 sec. The receptionists btw have a shared line on our main DID. We prefer to speak to the caller directly instead of letting him go to a voicemail system.

It would be possible, just as you suggested, to setup a shared dual line (octo is not necessary) on every phone but in this case I would sacrifice a button on each phone for a thing that normally wouldn't need any buttons .

Maybe I could settle with an overlay-dn on phones that are short on buttons.

Using overlay-dns might also solve another problem that I'm currently having. If some calls our main-DID, as described earlier, the two phones of our receptionists ring. Both phones should ring at the same time, since they are never at the same time in the office (yes I know they also could ephon-hunt with logon/logoff... but the laziness of girls... well...).

After 20 sec or so I want to add phones to those that already are ringing. After another 20 sec. all phones in the office should ring. I could define 3 ephone-dn's  like 701, 702 and 703. Add all three on the receptionists overlay button add 702 and 703 on the phones that should also start ringing after 20 sec and all other phones only get their personal line and 703 on the first button. Would such a setup cause any unforseen trouble? Would a "CFwdALL" on any phone affect those overlayed lines?




Yes, you can use overlay DNs as you described, for a "widening ringing phone circles" effect.

CF settings do not affect overlaid DNs.

It's remarkable how some people failure to press a button on the phone is the same everywhere... but then they won't forget to check some popular social website multiple times a day.

Thank you for the nice rating and good luck!