Topcom SOLOGIC B901 COMBO Short User Manual page 16

Call forwarding and internal calls
INT
4 5 6
J
G M
H K N
I L O
16
1 In standby mode, press the INT key and then the
number of the handset (1-5, select "0" for the base
station).
The handset or base station you have called will now
ring.
2 Press the call key or pick up the receiver on the
base station.
You can now talk internally.