Resources
Guides to SIP trunking, phone systems and numbers
Practical, vendor-neutral explanations for the people who choose, configure and support business phone systems. Each guide separates general industry practice from settings that depend on your provider.
- 7 guides
- Vendor-neutral
- Written for IT teams
All guides
Browse the guides by topic
Start with the fundamentals if SIP is new to you, or go straight to planning and setup if you are preparing a deployment.
Understand the options
What SIP trunking is, and how it compares with traditional lines and hosted phone systems.
- Fundamentals · 7 min read What is SIP trunking? How a SIP trunk connects a phone system to the public network, and what a channel really is.
- Comparison · 7 min read SIP trunking vs traditional phone lines Analogue lines, ISDN/PRI and SIP compared on capacity, flexibility, resilience and migration effort.
- Comparison · 6 min read SIP trunking vs hosted PBX Keep your own PBX and add trunks, or move the whole phone system to the cloud? A decision guide.
Plan, connect and secure
Practical guidance for sizing a trunk, connecting a PBX and protecting it against misuse.
- Setup · 9 min read How to connect a PBX to a SIP trunk A step-by-step, vendor-neutral walkthrough: authentication, codecs, NAT, routes and testing.
- Planning · 8 min read How to estimate SIP channel requirements Size concurrent calls from real busy-hour data, with worked examples and bandwidth maths.
- Security · 8 min read SIP trunking security best practices Prevent toll fraud and service abuse with layered controls on the PBX, network and trunk.
Numbers
How phone numbers are supplied, routed and moved between providers.
Where to start
Suggested reading by situation
If you have a specific project in mind, these guides cover the questions that usually come first.
You are replacing analogue or ISDN lines
You are deciding whether to keep your PBX
You are configuring a PBX for a new trunk
You need numbers in new locations or want to keep existing ones
Services and questions
From guidance to a working configuration
The guides explain general practice. Our services apply it to your phone system, network and numbers, with settings confirmed per deployment.
- Voice SIP Trunking Connect your existing IP PBX to the public phone network for inbound and outbound calls.
- Cloud Cloud PBX A hosted phone system with extensions, IVR, queues and voicemail, with no PBX on site.
- Numbers Virtual Numbers Local, national and toll-free numbers (DIDs) routed to your PBX, trunk or cloud system.
- Questions Frequently asked questions Short answers on SIP basics, numbers and coverage, pricing and setup, and security.
Next step
Have a question the guides do not answer?
Describe your phone system and what you are trying to achieve. We will reply with specific recommendations and, if useful, an itemised quote.
Helpful to include
- PBX platform, or plans for one
- Users and peak concurrent calls
- Numbers to port or order
- Countries you call or need numbers in