Call Transfer on Draytek 2800VG using POTS phone

We are hoping to use the 2 VOIP ports on the Draytek router in place of our standard SNOM phone for small remote locations.

The phones work well for answering and making calls but I have not been able to transfer calls either blind or attended. Is there a function to do this and what is the key sequence?

I have tried #extension and **extension which was suggested by our support company but they did not seem to work.

Thanks

You need to change in dial plan for trnasfer the call. For ex:
Dial(2000, 30, tT) tT means u can transfer your call.