Which public switched telephone network (PSTN) service provides small businesses with an inexpensive alternative to purchasing and running a private branch exchange (PBX)?

Voice over internet Protocol (VoIP) services provide small businesses with an inexpensive alternative to purchasing and running a private branch exchange (PBX). VoIP allows businesses to make phone calls over the internet, reducing costs associated with traditional PSTN services. Additionally, many VoIP providers offer features typically found in PBX systems, such as call routing and voicemail, without the need for extensive hardware. This makes it a cost-effective and flexible solution for small enterprises.