The SIP telephone can be an IP phone or a softphone running on a PC. It can be registered in the Abilis private or public side.
The configuration varies depending on the telephone is behind a NAT.

Enter into the Abilis control-program or open the configuration file with the Console configurator and type the following commands.
| a
            res:ctisip or s act res:ctisip | Add the CTISIP resource. or If the resource already exists, set it active. | 
| s p ctisip act:yes | Enable the CTISIP runtime functionalities. | 
| a user:sip_phone pwd:sip_phone sip:yes | Add the username and password associated to the SIP telephone and enable it to SIP protocol. | 
| s user:sip_phone sip-number:61 | Configure the SIP telephone number. | 
| s user:sip_phone sip-maxses-bid:4 | Configure the maximum number of SIP bidirectional sessions. | 
| save conf | Save the configuration. | 
On a working Abilis, a system restart is required to make the CTISIP resource running.
| ![[Note]](../images/note.png) | Note | 
|---|---|
| It is possible to specify a FQDN in the  | 
| ![[Note]](../images/note.png) | Note | 
|---|---|
| The previous configuration can be applied also when a SIP Proxy
      must register itself onto Abilis. In this case the proxy is a
      “normal” user like a SIP phone but the
       | 
| ![[Tip]](../images/tip.png) | Tip | 
|---|---|
| For the softphones configuration refer to Chapter 76, Softphones. | 
Enter into the Abilis control-program or open the configuration file with the Console configurator and type the following commands.
| a
              res:ctisip or s act res:ctisip | Add the CTISIP resource. or If the resource already exists, set it active. | 
| s p ctisip act:yes | Enable the CTISIP runtime functionalities. | 
| a user:sip_phone pwd:sip_phone sip:yes | Add the username and password associated to the SIP telephone and enable it to SIP protocol. | 
| s user:sip_phone sip-number:61 | Configure the SIP telephone number. | 
| s user:sip_phone sip-maxses-bid:4 | Configure the maximum number of SIP bidirectional sessions. | 
| s user:sip_phone sip-remote-nat:strict | Configure the NAT trasversal method. | 
| save conf | Save the configuration. | 
On a working Abilis, a system restart is required to make the CTISIP resource running.
| ![[Note]](../images/note.png) | Note | 
|---|---|
| Users which are registered onto Abilis and that stays behind the
        same NAT, i.e. that presents themselves to the Abilis with the same IP
        address, can be configured (with
         | 
| ![[Note]](../images/note.png) | Note | 
|---|---|
| It is possible to specify a FQDN in the  | 
| ![[Note]](../images/note.png) | Note | 
|---|---|
| The previous configuration can be applied also when a SIP Proxy
        must register itself onto Abilis. In this case the proxy is a
        “normal” user like a SIP phone but the
         | 
| ![[Tip]](../images/tip.png) | Tip | 
|---|---|
| For the softphones configuration refer to Chapter 76, Softphones. |