[Asterisk-Users] snom 190: dial tone without registration?

[alan]

Hello.

I'm currently evaluating the Sipura SPA-841, and snom 190 phones for use
in an Asterisk PBX/call center environment.

One feature the SPA-841 has, which I can't figure out how to implement
on the snom 190, is the "make/accept calls without registration"
feature. Or more specifically, "produce a dial tone even if I'm not
registered."

I would like to set our sip.conf entries to "host=<ipaddr>" instead of
"host=dynamic" to enforce the IP addresses used by each sip phone. If we
do this, Asterisk does not accept SIP registration from the phone on
that IP. This is fine with the SPA-841, but the snom 190 displays a "NR"
status (Not Registered), and refuses to play a dial tone when you take
the phone off-hook. The phone will place calls correctly, but it insists
on thinking it's in an error condition when it can't register.

Note that Asterisk's "defaultip" option in sip.conf isn't adequate,
because it doesn't deny access if the phone attempts to register from a
different IP.

Does anyone know how to do one of the following:
- tell the snom 190 not to register, but to use the outbound proxy for
  outgoing calls, and produce a dial tone anyway.
- tell Asterisk to enforce an IP address restriction for a specific SIP
  channel, but still accept an incoming registration from that IP.

Vitals:
- Asterisk 1.0.7
- snom 190 firmware 3.60i


Thanks,

Alan Ferrency
pair Networks, Inc.
alan at pair.com