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Frequently asked questions and answers

  • Why opt for a VoIP system and who handles the migration?

    Why opt for a VoIP system and who handles the migration?

    Why opt for a VoIP system and who handles the migration? Voice Over IP (VoIP) communication servers have the major advantage of being able to use the existing cabling of the data network. It is even possible to connect your telephone to the same cable as your PC. Telecom-IT provides both a full VoIP communication server and a hybrid system. Hybrid systems combine modern VoIP technology with older digital technology, meaning that we are perfectly positioned to meet all of the needs of our customers.

    And that’s right, Telecom-IT really does handle everything when you buy a new communication server. From retrieving, cancelling and moving telephone numbers, checking your call plan rates and adjusting the cabling, to installing the new system and providing the training required.

  • VoIP/SIP telephony: I can make calls, but cannot receive them

    VoIP/SIP telephony: I can make calls, but cannot receive them

    To be able to make calls over VoIP, a number of ports in your firewall have to be open. This is necessary because otherwise VoIP traffic would be blocked. To be certain when you have connection problems that your firewall is not blocking incoming calls, the best thing to do is switch off your firewall. There are various types of firewall, and these are usually subdivided into 'software firewalls' and 'hardware firewalls'. It is possible that you have both.

    Software firewall:
    This firewall (personal firewall) is a program that is installed on your PC.

    Hardware firewall:
    A (WLan) router usually has a built-in firewall, although there are also dedicated hardware firewalls.
    These firewalls can be accessed in various ways. If necessary, consult with your system manager to have your firewall adjusted.

    Open the following ports in your firewall:
    - SIP: 5060 / TCP
    - SIP: 5060 / UDP
    - RTP: 10000 - 20000 / UDP