PAP2T not work with GE cordless phone

[ding]

Hi, I need help.
I have a PAP2T connect to freephoneline.ca, it works ok when I use cord phone, when I switch to GE cordless phone, I am seeing problem:
1) if I dial the number then press talk button, I can connect.
2) if I press talk(or hand free) then dial the number, it failed, I checked the "Info" page from PAP2T, the last called number is not what I dialed.

Is it possible a problem for regional setting ? like tone frequency ?

Also, does not matter what kinds of phone I am using, after pickup to dial, the first tone come out is a busy tone, and after a few second, it switch to a dial tone , and then I can dial. what can cause this problem ? dial plan ?

Any comment is welcome!!
Din