Siemens Gigaset S450 IP

Just replaced my C450 IP with S450 IP, mostly for multiple SIP accounts support.

Good things:
– can connect to up to six SIP accounts at the same time, plus
– can map SIP account and fixed line to DECT phones (both outgoing and incoming calls)
– reasonable DECT coverage
– NAT traversal using STUN
– works with asterisk
S45 handset can be registered to multiple bases, allowing you to chose base or just best signal base

Bad things:
– can not choose what SIP account to use for outgoing calls on a call-by-call basis
– calls never worked for me
– R-key does not work with SIP
– no MWI (Message Waiting Indication) for VoIP calls
– slow handset response sometimes (tested with S45, C45 and C46 handsets)
– no automatic phonebook synchronization between handsets

One very interesting feature would be the possibility to use the Phone Line as a regular FXO port, allowing PSTN-to-VoIP and VoIP-to-PSTN calls.