Old PBX, new tricks

May 2025

Some years ago we began supporting a small business with an Avaya IP Office PBX that was originally installed by BT in 2012. They are a small wholesale supplier of food and ingredients to pubs and restaurants. During the day calls work as in any typical business. During the evening and overnight, and over the weekend, chefs and restaurant owners call in and leave their orders which are stored in a voicemail box for retrieval the next working day.

I just took a call from the business owner saying they have a scheduled mains power shutdown for 9 hours starting at 3pm and they wanted to know how they could avoid missing calls and orders being left in the evening.

In fact, I was able to tell them that there was already a solution in place that would deal with this or any other more unpredictable failure on site!

When we migrated the phone lines connected to the Avaya PBX from ISDN to SIP, we also set up a PhoneLine+ service; a Cloud single business line that also feeds calls into the phone system via their backup internet connection. Gamma SIP Trunk Call Manager automatically re-routes incoming calls for the business’s main phone number to the PhoneLine+ line if the call cannot get through on the main SIP connection. If there is still no answer, PhoneLine+ provides an independent Cloud-hosted voicemail service which e-mails an MP3 recording as well as a transcription of the voice message.

If the business ever needed to do so, they could answer their business calls or call out via a Softphone on a Smartphone app or via a browser, PC or Mac Softphone app anywhere with an internet connection, using PhoneLine+.

In this case, the customer continues to benefit from the investment they already made in an on-premise PBX that perfectly fits their needs, whilst having additional resilience due to smart features of Gamma SIP Trunking and a PhoneLine+ failover service.