Multiple Subscriber Number (MSN)

ISDN is the technology that brought digital functionality to the traditional phone network, otherwise known as the Public-Switched Telephone Network (PSTN). In particular, ISDN enables the simultaneous transmission of different types of data, such as voice and video, over the PSTN. 

In the near future, ISDN will be decommissioned across Europe in favour of voice-over-IP (VoIP) technology, which routes phone calls across the internet rather than the PSTN. In the UK, BT has already announced that ISDN will be decommissioned in the next few years, while the date set for decommissioning in Germany is 2018. VoIP technology is far more efficient and cost-effective than ISDN, which is one of the main reasons it is being decommissioned.

MSNs are used to ensure that every device on the network has a different phone number. Additionally, they allow users to make two voice calls simultaneously over a single ISDN connection. When a phone call enters the ISDN network, it is delivered to the specific MSN via the S0 bus.

NOTE: One device can have multiple MSN numbers allocated to it.

VoIP solutions such as the NFON Cloud Telephone System are much more flexible than MSNs. This is because MSNs are static numbers that are allocated to fixed points in the network, whereas VoIP connections allow users to log in from anywhere, using any device. 

This means that with MSNs, employees visiting different offices are not able to use their own phone numbers and can only communicate using local numbers at that office. With VoIP, they can simply log into the remote office network and use their own phone number to contact colleagues or customers.

For more information about MSNs and other telephone technologies, or to discover the benefits of the NFON Cloud Telephone System, please review the articles below: