// learning path · beginner → advanced

Voice Modernisation (PSTN → Cloud)

3 articles · ~32 min total · Updated May 2026

A three-step path for Singapore businesses migrating off legacy fixed-line and ISDN telephony. Start with the fundamentals of VoIP, layer on SIP trunking to replace your physical lines, then dig into the Session Border Controller — the security and interoperability gateway you almost certainly need but rarely hear about until something breaks.

Start with Step 1 →
1

VoIP Fundamentals: How Voice Over IP Actually Works

What VoIP is, how a phone call becomes IP packets, the protocols (SIP, RTP) and codecs (G.711, Opus) involved. Foundation for the rest of the path.

Beginner 9 min · Voice & Telephony
2

From PSTN to SIP: Modernising Business Telephony in Singapore

Replacing legacy fixed lines and ISDN with SIP trunks. What SIP trunks are, how they're priced, who you can buy from in Singapore, and a step-by-step migration playbook.

Intermediate 11 min · Voice & Telephony
3

Session Border Controllers (SBCs) Explained

The security, interoperability and transcoding gateway that sits between your PBX and your SIP trunk. What an SBC actually does, where it sits, and why you almost always need one.

Advanced 12 min · Voice & Telephony

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