SIP TA
The Centro Business features an integrated SIP Terminal Adapter (SIP-TA). This allows IP telephones to be registered directly on the router and use the subscribed phone numbers.
The SIP-TA provides local SIP credentials with which compatible IP phones or soft clients in the local network can be registered on the Centro Business. This allows the router to function as a local SIP instance, supporting IP telephones as well as analog/ISDN terminals in parallel.
Expert function
This function should be configured exclusively by experienced IT specialists. Errors can lead to critical security vulnerabilities that may negatively affect both the customer installation and the Swisscom reputation.
Configuring the B2BUA in the Centro Business
- In the router portal under VoIP → Basic Settings (VoIP), select the desired number and click "Change"
- IP telephone number and authentication username are fixed — enter them as-is in the SIP phone/soft client
- Authentication password can be changed or used as provided
Saved passwords are persistent thanks to Easy Activation and remain available even after a reset.
Configuring the SIP phone
The following SIP credentials must be entered in the SIP phone or soft client:
| Parameter | Description |
|---|---|
| IP telephone number | Number provided by the router |
| Authentication username | Fixed value |
| Authentication password | From router portal (changeable) |
| Registrar IP address | Local IP address of the router (e.g. 192.168.1.1) |
Configure further parameters according to the operating instructions of the respective SIP phone or soft client.
Prerequisites
- At least one phone number registered on the Centro Business
- Telephony LED glows white or green depending on the subscription
- SIP phone or soft client supports SIP standards (RFC 3261)
- Free configuration of SIP credentials on the device is possible
FAQ - SIP-TA
What is a SIP-TA or B2BUA?
The Back-to-Back User Agent (B2BUA) is a VoIP software component in the Centro Business that acts as an intermediary between the central Swisscom VoIP Application Server (VoIP AS) and any SIP client. It controls connection establishment, signaling, and media streams during a VoIP call.
What are the password requirements?
- Minimum 8 characters, maximum 128 characters
- Minimum 1 lowercase letter
- Minimum 1 number (only 1–9)
- Not allowed: All uppercase letters and special characters, l (lowercase L) and the number zero (0)
What needs to be considered when changing router models (CB 2.0 → CB 3.0)?
With the Centro Business 3.0, password security for the B2BUA authentication password was revised. Instead of the phone number being preconfigured as the password (as with CB 2.0), a more complex password is generated. If SIP was already used with the phone number as the password, the new authentication password must be taken into account when commissioning the CB 3.0. If the password already met the requirements before the model change, it is carried over.
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