FRITZ! Fon 7150 - simultaneous SIP calls - how many?

[yakall]

Hi,
How many simultaneous SIP calls will handle the FRITZ! Fon 7150?
I know that you can connect up to 6 handsets, set up 10 SIP accounts, but how many of these handsets can be in simultaneous use?

P.S. I'm sorry that after English, but I do not know the German language :-(

Pawel

------------------------------
Fritz!Fon 7150 with speed2fritz
FRITZ!Box Fon WLAN 7170 (7150) Firmware-Version 29.04.87

 

[vipost]

1x fixed line, + 3x VoIP (with SIP-Server IP-Phone inkl.)

 

[mikrogigant]

If connected to ISDN, the 7150 can handle 2 ISDN Calls + 3 SIP-Calls simultaneously.