Question 1

What's the difference between SIP trunks and hosted VoIP?

Accepted Answer

Hosted VoIP replaces your entire phone system with a cloud-based one (no PBX hardware on your premises). SIP trunks replace ONLY the carrier connection — your existing PBX stays, you just swap ISDN/PSTN lines for SIP. Hosted VoIP is more modern and feature-rich; SIP trunks are the right path when you've recently invested in a good PBX and want to preserve it.

Question 2

Does my PBX support SIP?

Accepted Answer

Most modern PBXs (post-2010) support SIP trunks natively. Older PBXs may need a SIP card added (£200-500 hardware cost). Very old PBXs (pre-2005) may not be SIP-capable — at that point hosted VoIP is usually the better path. We audit your PBX in the initial survey.

Question 3

How many channels do I need?

Accepted Answer

One channel = one concurrent call. If you have 20 staff but rarely have more than 10 on the phone simultaneously, 10 SIP channels is enough. We measure your actual concurrent usage from CDRs before recommending — it's almost always lower than people guess.

Question 4

What about emergency calls (999)?

Accepted Answer

Full 999 support is mandatory on SIP trunks just like ISDN. Address registration is required (Ofcom mandate) so emergency services see the right location when dispatched. We handle this during setup.

Question 5

Is SIP quality as good as ISDN?

Accepted Answer

On a properly-engineered business broadband (FTTP with QoS): yes, often better than ISDN. On a residential-grade connection or one without QoS: probably worse. SIP needs the underlying internet to be solid. We always verify broadband quality before quoting SIP.

Question 6

What happens if my internet drops?

Accepted Answer

Without failover: SIP trunks go down. Standard mitigation: 4G/5G failover keeps SIP trunks live during broadband outages. Or: SIP calls auto-divert to mobile numbers / alternate sites. ISDN doesn't depend on broadband but SIP does — failover planning is essential.

Question 7

Can I migrate gradually from ISDN to SIP?

Accepted Answer

Yes — common for larger businesses. Run SIP alongside existing ISDN for 30-90 days, port numbers in batches, decommission ISDN channels as confidence builds. Both can coexist for as long as needed.

Question 8

How much do SIP trunks cost?

Accepted Answer

Per-channel pricing: £5-12/month depending on bundle. 10-channel SIP trunk with 5,000 UK minutes included: £80-120/month all-in. Compare to typical 10-channel ISDN30 at £400-600/month and the savings are immediate.

SIP trunks in Manchester.

Review my current setup

Modernise without replacing.

Connect your PBX

Cut costs

Keep numbers

ISDN is being switched off.

PSTN switch-off

Flexible

UK support

Across Manchester and the surrounding areas.

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