Cut your telecoms bill by up to 70%.
SIP trunking eliminates ISDN line rental, reduces per-minute call rates, and makes site-to-site calls free. Most UK businesses save between 50 and 70% on their telecoms costs from day one. IP Four shows you the exact saving before you commit.
50-70%
typical reduction in telecoms costs when switching from ISDN to SIP trunking
0p
cost for calls between your offices on SIP trunking. Free site-to-site calls included
60-80%
cheaper international call rates on SIP versus traditional PSTN pricing
UK-wide
cost reduction delivered for businesses across all UK regions
Every way SIP trunking reduces your costs.
No Line Rental Charges
ISDN line rental is one of the largest hidden costs in business telephony. SIP trunking eliminates line rental entirely. You pay for channels and calls, not for physical lines sitting idle.
Free Site-to-Site Calls
Calls between your offices travel over your IP network at zero cost. Multi-site businesses with high internal call volumes see the biggest savings. No more paying per-minute for internal calls.
Lower Per-Minute Rates
SIP trunking per-minute rates for UK landlines and mobiles are significantly lower than ISDN equivalent rates. International calls are typically 60 to 80% cheaper than traditional PSTN rates.
Transparent Billing
Itemised billing for every call. No hidden charges, no rental surprises, no minimum usage commitments. You see exactly what you are paying for and can challenge any anomaly immediately.
Inclusive Call Bundles
Monthly call bundles available for businesses with predictable call volumes. Fixed monthly cost for UK landline and mobile calls. Budget certainty without sacrificing flexibility.
Cost Benchmarking
We benchmark your current telecoms spend against SIP trunking equivalents before you commit. You see the exact saving before migration begins. No surprises, no estimates.
We show you the saving before you commit.
Telecoms Spend Audit
We review your current bills, line rental charges, call costs, and any maintenance contracts. Build a complete picture of what you are currently spending and where the waste is.
SIP Cost Modelling
Model your exact costs on SIP trunking based on your actual call volumes and channel requirements. Show you the monthly saving before any migration begins.
Contract Review
Review your existing ISDN contracts for early termination clauses and notice periods. Plan the migration timeline to minimise any overlap costs.
Migration and Cutover
Migrate to SIP trunking with zero downtime. ISDN lines cancelled only once SIP is confirmed stable. No period where you are paying for both.
Bill Validation
First three months of SIP billing reviewed against the cost model. Any discrepancies investigated and resolved. Confirm the saving matches what was projected.
Ongoing Cost Management
Annual telecoms cost reviews included as standard. Proactive recommendations when better rates or bundles become available. Your costs managed, not just your lines.
Real savings delivered across the UK.
Challenge: A London professional services firm was spending 3,200 pounds per month on ISDN line rental and calls across two offices. They had not reviewed their telecoms costs in four years.
Outcome: SIP trunking deployed across both offices. Free inter-office calls enabled. Monthly telecoms spend reduced to 1,100 pounds. Annual saving of 25,200 pounds. Migration completed in one weekend.
Challenge: A Yorkshire retail chain with 6 stores was paying separate ISDN line rental at each location and high per-minute rates for calls between stores and head office.
Outcome: Single SIP trunk provider across all 6 sites. Free inter-site calls. Line rental eliminated. Monthly saving of 1,800 pounds. Full ROI achieved in the first month after migration.
Challenge: A Birmingham healthcare provider had high volumes of outbound calls to patient mobiles. Their ISDN mobile call rates were significantly above market rate on an auto-renewing contract.
Outcome: SIP trunking with inclusive mobile minutes bundle. Mobile call costs reduced by 65%. Total monthly telecoms saving of 940 pounds. Contract flexibility restored with 30-day rolling terms.
Find out exactly how much you could save.
Send us your last three months of telecoms bills and we will produce a detailed cost comparison showing your exact saving on SIP trunking. No obligation, no pressure. Just the numbers.