Save money and install or upgrade to IP Telephony with Flow Telecom. Replace rigid, expensive ISDN solutions with flexible Flow Telecom SIP Trunks and Hosted Telephony services. In 2015 BT announced that they will be switching off the PSTN and ISDN in 2025, marking the biggest change in the telecoms industry for over 30 years.  In Short, before 2023 you…