This feature is under investigation and is only allowed to be used with support from Gigaset, please contact your local Technical Sales if you would like to use this feature.

With this new feature, the N720 is connected with other platforms via IP address instead of using the SIP registration method. This feature allows:

  • Connection to Cisco platform using the Cisco Call manager
  • Providers that connect via IP address and not using SIP registration
  • SIP trunks provided by PBX systems or Internet Service Providers

After successful trial period, this feature will be official released.

N720 Software version

This feature can be used with the N720 Release 89 and higher.

N720 configuration

In this example we have the following set-up

  • PBX has IP address
  • All numbers starting with "2" are routed to the N720
  • N720 has IP address
  • SIP accounts are configured using the internal numbers of the PBX.
    • Number 200 has username 200 and Password 200
    • Number 201 has username 201 and Password 201
    • .....
  • The internal number is in the Invite header, the PBX dials 200 and the Invite with number 200 is send. Device/handset with number 200 will ring.

Provider configuration

DomainIP address of Platform
Proxy server addressIP address of Platform
Registration serverlocalhost
Outbound server addresslocalhost
Outbound proxy modeNever

User/device configuration

Authentication nameInternal phone number
Authentication PasswordN.A.
UsernameInternal phone number
Display nameInternal phone number
(Can be seen on display handset)

PBX configuration

We used the Gigaset T640/T440 in this example.

SIP Gateway configuration

RegistarIP address of N720
RegisterNo (No SIP registration)
GroupGateway group

Gateway Group

Create a new gateway group with these settings.

Outbound routes

All numbers starting with 2 will be send to N720

The Cisco configuration is the same when you connect to an Asterisk PBX.

  • Cisco CUCM does not like multiple “extensions” to REGISTER the same contact address (IP:port)
  • For multiple extensions (numbers) at the same transport destination Cisco CUCM prefers to configure a “trunk” down to N720/N510
    Trunk means in this case:
    • CUCM learns the transport destination of such “trunked” extensions (numbers) just by a local configuration inside CUCM
    • CUCM does not need and does not like to receive REGISTER requests from such “trunked” extensions

We have trick available in N510/N720 to achieve such behavior: “localhost REGISTRAR simulation”

Field name

example for CUCM trunk



<domain name or IP-address of the CUCM SIP service>

this is host part that our device uses to build an Address of Record (SIP-UIR) for this domain

SIP server (proxy)

<FQDN or IP-address of the CUCM SIP service>

-        all outgoing requests except INVITE will be send to this destination

-        all incoming request are expected from this destination

SIP registrar


-        all REGISTER requests will not leave the device but will be sent to the device it self

outbound proxy


-        incoming REGISTER requests will automatically be replied internally with 200 OK

outbound proxy mode


-        do not use the outbound proxy field as transport destination for all SIP requests

This way  all REGISTER requests stay internal of N510/N720 and are internally confirmed with 200 OK.

The MMI is happy about being successfully registered.

Any initial outgoing request (e.g. INVITE) are sent to the configured “SIP server” , e.g. the CUCM.
With the record-route header the CUCM can install any other proxy in the route set.

As we have used the outbound proxy server field  to indicate activation of a local registrar simulation, we don’t have it available to configure any other outbound proxy overruling the “recorded” routes of the CUCM  network.

If N510/N720 and CUCM are in different subnets, N510/N720 would usually send UDP packet { CRLF, CRLF }.
To disable that you can set NAT refresh time to 0.

If you need periodical SIP traffic to use the SIP trunk,
you could consider to use one account in the regular manner to register an extension at the CUCM but all the other accounts to do registration just with the “localhost REGISTRAR simulation” mentioned above.

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