SIP Provider Swisscom (CH) - Smart Business Connect (kb4827)

The information in this article applies to:

  • SwyxWare 11.00
  • SwyxWare 2015
  • SwyxWare 2013

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Information und configuration hints for SIP provider Swisscom (Switzerland), product: Smart Business Connect


General information

On behalf of the customer, the partner orders the Smart Business Connect trunk (SBCon) from Swisscom. Swisscom will deliver an appropriate gateway with eSBC functionality (Cisco 881 or Cisco ISR 4321). This eSBC will act as a SIP trunk for the SwyxWare and performs the call signaling towards the Swisscom. A profile for the SwyxWare ist installed on the eSBC which is synchronized with the SwyxWare configuration.

For the connection from the SwyxWare to the eSBC, it must be assured that the eSBC in the customer's network is configured with a static IP address.

Configuration of the SwyxWare

For your convenience the generated CustomProviderProfiles.config is available for download at the end of this article. Extended information about how to use this file can be found at Configuration and Adaptation of SIP Providers via Provider Profiles (kb3436).
Important: From SwyxWare 2015 R4 on, the provider profile for Swisscom is already available in the list of provider profiles and the CustomProviderProfiles.config is no longer necessary.
  1. Creation of a location with the information of the assigned number range
  2. Creation of a SIP trunk group with the Swisscom SBCon profile "Swisscom_SBCon (CH)"
  3. In the properties of the SIP trunk group, within the tab "SIP", the IP address and if necessary, the port of the eSBC have to be configured in the field "Registrar" and in the field "Proxy"
  4. Creation of a SIP trunk underneath the newly created SIP trunk group
  5. Enter user credentials for registration
  6. Configuration of the assigned number range

Additional settings

CLIP No Screening
To activate feature CLIP No screening, in the tab 'Number Signaling' of the trunk properties the option 'Always use originator's number' must be set.

FAX transmission
The eSBC for theSBCon supports the T.38 protocol, which was developped for FAX transmission via IP. However, T.38 must not be offered in the initial INVITE for an outgoing FAX. In the SIP trunk properties, underneath the tab “Codecs/Channel”, the option “Remove T.38 from initial invite” has to be selected. After the FAX tone was detected by the SwyxWare, it will send a reINVITE which only offers T.38.
Note: In case that FAX transmission has to be carried out through G.711 exclusively, T.38 has to be deselected in the list of supported codecs. This is not recommended since FAX transmission via T.38 is supplying a significantly better quality, stability and reliability.
At the end of this article, you find a recommenndation from the Swisscom about handling of analogue FAX machines.

To successfully transmit DTMF signals through the Swisscom trunk, it is necessary to increase duration of the DTMF signals in the SwyxWare. To do so, a new registry key underneath  HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Swyx\LinkMgr\CurrentVersion\Options

must be created with the exact name of the created SIP trunk. Underneath this new key, a new DWORD value named DTMFToneDuration has to be created. A value of 800 (dec) must be assigned to that value and the LinkManager must be restarted.

Session interval
The eSBC for the SBCon expects a session interval of 1800 (seconds). In order to prevent reINVITES, which would slow down call establishment, in the Windows registry on the SwyxWare server, underneath HKLM\SOFTWARE\Wow6432Node\Swyx\LinkMgr\CurrentVersion\Options
two new DWORD values with following name and value need to be created:
SipSessionTimerIntervalSeconds:   1800 (decimal)
SipMinSessionTimerIntervalSeconds: 360 (decimal)

Finally, the LinkManager service needs to be restarted.
Important: These settings will affect all SIP trunks.


Tested Features

  • Incoming/outgoing national calls
  • Incoming/outgoing international calls
  • Correct Calling Line Identification (CLI) on national and international calls
  • CLIP No Screening
  • Holding and retrieving calls
  • Toggeling between two calls
  • Call transfer
  • Conferencing
  • Mutually supported codecs:
    • G.711a
    • G.711µ
    • G.729
    • T.38
  • Incoming/outgoing DTMF signaling in accordance with via RFC2833

Test date:

15/06/2016 with SwyxWare2015R3

Overview of tested SIP provider


As far as software supplied or used by us, includes open source elements the additional terms under apply in addition. An overview which products from the Swyx portfolio include open source elements and which open source license is relevant can be found under

The third-party contact information included in this article is provided to help you find the technical support you need. This contact information is subject to change without notice. Swyx in no way guarantees the accuracy of this third-party contact information nor is responsible for it's content.


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