Need help with VOIP adapter

Quick explanation. Bought a Camrivox (aka Flextor) UTA-151 VOIP adapter (in fact 2, have one at home as well). Set it up for incoming calls at our radio studio, so we would have several geographic numbers on local exchanges.
It's been running fine for months. No outgoing calls, but that's not a problem, we don't need them. It's connected to a pair of DECT phones and sits in-line on the Ethernet to one of the 'always on' PC's.
All was fine until our old ADSL router went funny last week. Got a new router, all Internet services back up and running as well as internal network. But, VOIP not working as I cannot connect to the unit.
It used to pick up an IP address on the network like 192.168.2.9 and I could open a web page at that address for the management page. At home it originally gave me 10.20.30.40 as the address to use.
No matter what address I try, it will not connect. The only way to configure the unit is via the management page, even the reset mode is there.
I've tried putting the old router back on but it gives the same message, "network settings are being determined". It does not fail and go back to setup mode, even after 2 days it gives the same message.
We've no VOIP without the unit. There's no support as the makers have discontinued the model. To replace it is too expensive (we are a voluntary community radio station).
Suggestions please?

Try connecting a standard phone to it, go off-hook and listen, then dial #

It should tell you it's IP address, etc. That might give you a start.

G

Hi and thanks for that.

I have a normal phone connected to the output at present, rather than DECT, and when you pick up you get the failsafe mode message I mentioned. Pressing # repeats the end of the message, after 'entering failsafe mode because...'. Pressing anything after that does nothing.

On initial setup I picked up the handset and pressed hash twice to get the IP address but that is not available now.

'Voice Connect' software is supplied with the device but that reports that there is no device to configure.

Doing a scan of IP addresses from the router shows that the device is trying to connect but keeps failing. It needs an IP address and DHCP is active with a big enough range to allocate from.

To answer my own question, and provide a solution, should anyone else encounter similar issues...
The VOIP box has been 'stuck' with a default message telling me it is 'defining network settings' for over a week. Using some network monitoring software I could see it was trying, every few seconds, to connect to the DHCP server on the router but was failing.
I connected it back to the old router and had the same problem, I was unable to access anything as it was failing to get an IP address allocated.
I've spent a lot of time pressing buttons and eventually found a method to get access. Pick up the phone, listen to the message, press hash, hear the message again, press hash again - I was then invited to 'choose mode' - nothing about this in the manual! Press 3 and I was asked to 'enter IP address' and after a bit of trial and error I worked out it needed to be told what IP address to connect itself to so I gave it 192.168.0.8, the next available on the router. This has to be entered as 192*168*0*8*, yes, a trailing star to set it.
Imagine how many times I went round that loop before finding the correct way to do it !
To my amazement, I was then able to bring up a management web page using the IP address I had given it - at last!
My VOIP services are now back up and running, via the new router.
Maybe someone else who has the same device will benefit from this information...

As so often, persistence pays! I am sure that somebody will find your help invaluable! TVM

Meldrew