some notes on my config of SPA 3000

Problem when dialing out to BT line, DTMF tones were not being recognised by the BT exchange. This was fixed by changing the DTMF playback level from -16 to -12 (as per this forum posting from Brian Mattey).

Dial plan: (<*:>x.|999S0<:@gw0>|112S0<:@gw0>|x.<:@gw0>)

This means any number beginning * goes to the default SIP proxy (which is my asterisk box), with the * stripped off; 999 and 112 go straight to the PSTN line as soon as those digits are dialled; any other number also goes to the PSTN line, but only after a short timeout to determine the whole number has been dialed.

The effect is that numbers dialled on the handset end up being routed through the PSTN as before; numbers prefixed with a * end up going into the asterisk box where other interesting routing is configured.

to attempt get spa3000 to call a voip number whilst also ringing house phone:
(however it doesn't work properly -- I can't get it to make the phone
ring at the same time as the VOIP -- just the handset first and then
when that times out, it stops calling the handset and calls voip)

in pstn line tab / FXO timer values section:

pstn answer delay: 16  (was 16)
pstn ring thru delay: 1 (was 1)

in PSTN-To-VoIP Gateway Setup section:

pstn ring thru line 1: yes (was no)
PSTN-To-VoIP Gateway Enable: yes (was no)
PSTN Caller Default DP: 2 (was 1)
off hook while calling voip: no

in dialplans section:
dial plan 2: (S0<:benc@dildano-ip-address>)

in SIP settings section:
proxy: dildano's IP address

in Proxy and Registration:
Make Call Without Reg: yes (was no) (actually i think this one is 
needed to make outbound calls not inbound)
Ans Call Without Reg: yes (was no)

To get UK style tones, I found this pdf with SPA3000 settings.