Snom 320 problem with call forwarding

Maybe the solution is very simple.
I have Cisco 7960G phones and Snom 320 phones.
When I press *21xxxxx on a Cisco phone the call is forwarded to phone xxxxx no matter if it is a Cisco phone or Snom.

When I press *21xxxxx on a Snom phone it “says” it is forwarded to phone xxxxx but when I call the Snom it rings and the call is not forwarded to phone xxxxx


  1. Is there something different with a Snom ?
  2. Do I have to change something in the extensions.conf file ?
  3. Is this a bug or un undocumented feature ?
  4. A slack in my knowledge ?

Thanks in advance !

Kind regards,


I have a liitle update, maybe it will help others with my problem.

A Snom320 which I have for a few months can do an unconditionally call forward to another phone by pressing *21 ( in the Netherlands )
The Linux firmware is 3.38, application 6.5.10 and jffsv2 version 3.36.
The new Snoms320 are also installed with this firmware but are not able to do unconditionally call forwarding with *21

I was told there is a parameter Timeout(s) on the preference page which I have to set to &#180 ( at lower level the parameter is called “redirect_time!” . When I filled in this value in the textfield and after I press the Save button it disappear from the textfield. According me it must be a pointer or indirect addressing method.
It is weird but the new Snom320 can now do unconditionally call forwarding. When I do this with the other new Snoms320 it doesn’t work !


  1. What does &#180 means ?
  2. Why does it work with the first new Snom320 I filled it in and not the other new Snoms320 I have.
  3. What’s the difference with the “old Snom320” which can do unconditionally call forwarding without a problem although the parameter “redirect_time!” is not set. ( I checked in the settings overview )

THX in advance !

Unconditionally call forwarding with the Snoms320 works !
But why ?

In my extensions.conf:

with the following command
exten => 10006,1,Dial(SIP/${EXTEN},10) or
exten => 10006,1,Dial(SIP/10006,10)
unconditionally call forwarding with *21 is not possible for the Snoms320
it works for the Cisco7960G’s

with the command
exten => 10006,1,Macro(zapdial,${EXTEN},SIP/10006)
unconditionally call forwarding with *21 is now possible for the Snoms320

Can somebody explain me why ?
Why does it work with Cisco and not with Snom ?
Is it a matter of SIP version difference ?