Linksys/Sipura SPA941 problems

I’ve got a weird problem with a Linksys (Sipura) SPA 941 phone.

When I dial an outbound external call I hear both the telco’s dialback tone and also the SPA941-generated dialing tone - so I get 2 different dial back tones at the same time.

I’ve asked Sipura tech support about this and they have recommended turning off the Dial Back tone in the Reginal Settings - but when I do this and dial an internal extension I then get no dialback tone (whether I use ,r or not on the DIAL command).

I’ve tested the setup with a Snom hardphone and SJPhone and both of these phones work without the double dialback tone problem. I’d say, it therefore looks like a problem with the SPA941, rather than the line/phone configuration.

Has anyone else had problems with this? Is there anything I should be checking?

I’m in the UK, using a 1 port Digium PRI card, connected to a BT ISDN30. I’ve upgraded the SPA941 to the latest firmware.

Other than this problem the SPA941’s are great phones and I’l like to use them in future deployments, but it looks like for now I’ll be sticking to the Snoms.