Fixed-line telephone (IP) and telephone number

On this page:
Learn how to connect your IP telephone and order a telephone number. Find out how to forward calls internally or hide your number.

Connect fixed-line telephone

With new IP fixed network telephony, fixed-line telephones are connected to the Internet-Box instead of a phone socket. You will still be able to use older analogue telephones that are not IP enabled, but will no longer be able to use some of the functions.

When you use a cordless HD-Phone for the first time, the telephone display will prompt you to press the + button (= pairing button) on the Internet-Box. In a few seconds, your HD-Phone will be connected. To set up the connection via the menu, follow the instructions for your device.

You will find additional instructions and information on cordless and corded fixed-line telephones on your device page. 

Go to device overview

Analogue fixed-line and cordless telephones with their own DECT base station are also connected to the Internet-Box.  Use a port labelled “phone” on your Internet-Box for this. If you are unable to establish a connection with your fixed-line phone, please change to frequency dialling in the settings (if possible). Telephones with impulse dialling can no longer be used.

You can also use your Swisscom fixed-network number with a SIP-enabled telephone from another provider. To use your third-party device, we recommend setting up SIP credentials. Alternatively, you can also configure your device locally with your Internet-Box.

Ordering/assigning telephone numbers

Order a new telephone number

In the My Swisscom (Customer Center) you can order additional telephone numbers (except SwisscomLine plus). Under "Manage products and services" > "Telephony" > "Adjust options".

Residential customers can use 2 telephone numbers, business customers up to 5. If you would like more telephone numbers, please contact us.

Assigning a number to a device

If you use an Internet-Box, you can assign phone numbers to devices as follows: 

  1. Enter or in your Internet browser and log in. Please note that you only have access to these settings when your home network is connected to your Internet-Box.
  2. In the left menu bar go to “Telephony” > “Settings”
  3. Set which phone number is to be displayed to the call recipient with “Outgoing call”. Use “Incoming call” to set which phone number rings out on the respective devices.
  4. Click on “Save”.

If you have a Centro Business, you can assign phone numbers to devices in My Swisscom: 

  1. In My Swisscom, go to “Devices” > “Device management”.
  2. Set which phone number should ring on individual devices (you can do this directly on the handsets if they are registered in Centro Business 2.0).

On a wired SIP phone, assign the phone numbers per device in the customer centre as follows: 

  1. Go to My Swisscom.
  2. In the device overview, select which telephone number should ring for which device.

If you are using a SIP telephone from a third-party provider (third-party device):

SIP Credentials
Local IP telephony

Suppressing phone numbers

For all calls

If you want to prevent your fixed network number or name being displayed to the call recipient, you can suppress your phone number. You will then appear to the call recipient as an anonymous caller.

For individual calls

If you wish to hide your number for specific calls, enter the following key combination on your fixed-line telephone before entering the phone number: *31, the number to be called, # (e.g. *310449999999#). This additional service is free.

Hiding a mobile number

If you wish to suppress your mobile phone number, enter *31#. You can deactivate the service again by entering the code #31#.

Forwarding calls internally

In-house forwarding

If several telephones are registered on your Internet-Box, you can use them to make free calls between these phones. You don’t need more than one phone number for this. You can, for example, assign the number 201 to your handset in the living room. You can then dial the internal number 201 on the phone in the bedroom to call your phone in the living room. You can assign the internal short numbers to the individual telephones in the web portal ( or 

Making or forwarding calls internally with a Centro Business 2.0 (HD-Phone Nyon, Gigaset SL360HS and Gigaset CL660HX) is also free of charge and does not require additional telephone numbers. However, you do need an additional phone number/line to forward calls on an IP-Phone (e.g. Yealink T46G, Sarnen HD-Phone) with inOne SME Office.

Internal forwarding is possible only from a cordless HD-Phone to another cordless HD-Phone or to an analogue telephone that is connected to phone port 1 or 2 on the Internet-Box.

Forwarding external calls internally

You can also forward an external call to another internal handset. Proceed as follows: 

  1. During the call, go to the ‘Options’ menu and select the ‘Forward’ menu item (alternatively, ‘New call’ or ‘Internal call’, depending on model). The INT button can also be used if available.
  2. Select an internal participant or the direct internal number, e.g. 204.
  3. Wait for the internal participant to accept the call.
  4. Go to the “Options” menu > “Forward” (for some models, you may need to select “Connect” or “Forward call”)
  5. The call will now be forwarded to the internal participant and you can end the call.

Frequently asked questions

Check the following points:

  • Handset battery is charged
  • Router is switched on.
  • Connected to the Internet (LED on Internet-Box is white)
  • No power failure

To ensure that you can still receive calls if there is a power cut or a connection problem, activate the supplementary service “Forwarding in the event of interruption” on My Swisscom(opens in new tab). You can set a number there to forward calls in the case of such a situation cropping up.

If the connection problem persists, please contact us.

The names of callers who have suppressed their own telephone number or name display do not appear on your telephone. The names of persons who are not registered in the publicly accessible telephone directory do not appear either.

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