Differences in Telephone Lines Explained
BT Openreach are making Analogue (PSTN) and Digital (ISDN) voice calls redundant by 2025. Let’s take you through the evolution of connectivity; from PSTN through to SIP and what this means for your business.
PSTN Lines (Public Switched Telephone Network)
Around for over 100 years, PSTN lines are a traditional land line that you would typically see at home or in a smaller office. These traditional lines provide the basics for communicating such as Caller ID and Call Divert and are limited to a single telephone number provided by BT.
ISDN Lines (Integrated Services Digital Network)
ISDN lines are Digital Lines and are more common than PSTN Lines in business, as you can have as many channels as you want. Larger businesses with departments tend to opt for ISDN due to the ability to provide DDI (Direct Dial) numbers for employees/departments. Calls can also be transferred to external numbers and includes Caller ID so users can see the number of the person calling them before they answer the phone.
SIP Lines (Session Initiation Protocol – VoIP)
By 2025, BT Openreach will have switched off both PSTN and ISDN lines moving everyone onto VoIP/Internet Telephony. SIP uses an the internet to connect a phone system to the telephony network provider. You still have access to all of the features provided by an ISDN line, with the added benefit of not being tied to any BT exchange,. This means you can select your own phone numbers with any Local STD code and display this when calling out.
As SIP Lines connect via an internet connection making SIP considerably cheaper than any landline type. It also provides increased flexibility and better Disaster Recovery solutions. The quality of the calls is related to the quality of the internet connection so you may need to upgrade your internet package, but over all VoIP is the way forward and BT Openreach are forcing the transition.
At Unified World, we would be delighted to support you in your transition from PSTN/ISDN to VoIP Telephony. You need to act now to avoid any potential disruption to your business, therefore please contact us and we’d be happy to discuss your requirements: email@example.com