Thanks all, for help and its almost working.
Outgoing call is working, they hear me but I can't here them.
Any sugestions what is wrong with my settings?


I used the following setting for the SPA-300;

On the system page:
Internet connection type;
Static IP: SPA-300 IP
Gateway: Router LAN IP
Netmask: 255.255.255.0

On the sip page (advanced mode):
STUN Server: stun.fwdnet.net:3478
(you can use any STUN server, they are not provider specific.)
change "Substitute VIA Addr" to yes
change "EXT IP" to the router WAN IP

On the Line 1 page:
Proxy: sip.voipbuster.com
Use Outbound Proxy: no
Outbound Proxy: (leave empty)
Register: yes
Display Name: (your voipbuster username)
User ID: (your voipbuster username)
Password: (your voipbuster password)
Gateway 1: sip.voipbuster.com
GW1 Auth ID: <UserID>
GW1 Nat Mapping Enable: yes
GW1 Password: <password>

On the regional page:
Caller ID Method: ETSI DTMF (for The Netherlands)

On the PSTN Line page:
Display Name: (voipbuster username)
User ID: (voipbuster username)
Password: (voipbuster password)

I used the following setting sugestions for the router type Thomson Speed
touch 510v4 ;
SPA-300 IP into the router's DMZ (De-Militarized Zone)
The NAPT settings are now as following for my configuration;
Type: Temp
Inside address: SPA-IP:0
Outside address: unspecified:0
Prot: tcp

No ports are specified


Credits to all who help me!!!

Cor