Keep the PBX You Own, Kill the Carrier Bill
PRI lines and legacy carrier contracts cost Boston firms $300+ per circuit for 23 fixed channels — whether you use them or not. SIP trunking replaces those circuits with virtual voice channels over your internet connection: burstable for peaks, priced per concurrent call, and portable across carriers.
Your desk phones, call flows, and staff training stay exactly the same — only the dial tone gets cheaper and more resilient. We run a SIP readiness check on your PBX, firewall, and bandwidth, then quote multiple carriers head-to-head. If your hardware is end-of-life instead, see Cloud PBX & UCaaS for the full replacement path.
Boston use case: the classic SIP win is a 30–100 user firm in Waltham or Burlington with a working Avaya/Cisco/Mitel system and two PRIs costing $700+/month. We trunk it over existing fiber with burstable SIP channels at half the cost, keep every handset and hunt group, and add mobile failover the PRI never had. Specialty analog lines stay put via our POTS replacement service.
PRI vs SIP Trunks: The Math
Why Boston firms with working PBX hardware switch the dial tone, not the system.
| Factor | Legacy PRI | SIP Trunking | Boston VoIP Advantage |
|---|---|---|---|
| Monthly Cost | $300+ per 23-channel circuit | $15–$30 per channel, pay for peaks only | 40–60% carrier savings, documented pre-sale |
| Capacity | Fixed blocks of 23 | Burstable, add channels in minutes | Sized to your real peak, not the circuit bundle |
| Hardware Change | None — but neither is progress | None — keep every phone and flow | Free SIP readiness check before you commit |
| Failover | Single circuit, single point of failure | Dual-carrier + mobile reroute capable | Paired with our internet failover designs |
| Contract | 3-year carrier lock-in typical | Flexible terms, portable numbers | Better-than-direct terms via master-agent status |
Send us your current carrier bill — we'll show the SIP math line by line.
Benefits of SIP Trunking for Boston Businesses
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40–60% Lower Carrier Spend
Replace $300+ PRIs with per-channel SIP pricing and burst only when call peaks demand it.
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Zero Retraining
Same phones, same extensions, same call flows. Staff notices the savings, not a new system.
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Burstable Capacity
Seasonal peaks and marketing surges absorb automatically — no ordering circuits months ahead.
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Multi-Site Consolidation
One SIP trunk group serves every office — Boston HQ plus Cambridge, Waltham, and remote staff.
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Gateway Path for Old Systems
No native SIP? A certified gateway bridges legacy PBX hardware to modern trunks.
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Carrier Redundancy
Dual-trunk designs with automatic failover — an outage stops being a busy signal.
Ideal For Boston Firms With Working PBX Hardware
SIP trunking tailored for paid-off systems, multi-site firms, and high call volumes.
Frequently Asked Questions
Common questions about SIP trunking for Boston businesses.
How much does SIP trunking cost in Boston?
SIP trunks typically cost $15 to $30 per concurrent-call channel per month versus $300+ per PRI — most Boston firms cut carrier spend 40–60%. Burstable trunks handle peak call volumes without paying for idle capacity year-round. We quote exact pricing from multiple carriers against your current bill.
Will SIP trunks work with our existing PBX?
In most cases, yes. Avaya, Cisco, Mitel, NEC, and 3CX systems from the last decade support SIP with a license or gateway. We run a readiness check on your PBX firmware, firewall, and bandwidth first — if your system can't do SIP natively, a low-cost gateway bridges it.
SIP trunking vs Cloud PBX — which is right for us?
Keep your paid-off PBX and staff workflows with SIP trunking when the system works and only the carrier bill hurts. Move to Cloud PBX when hardware is end-of-life, maintenance costs climb, or you need modern UCaaS features. We advise both and will tell you honestly when SIP is the smarter buy — see our Cloud PBX service for the replacement path.
Can we keep our Boston numbers and fax lines?
Yes. DIDs, toll-free, and most fax lines port to SIP. For specialty analog lines like alarms and elevators that shouldn't ride SIP, pair trunks with our POTS replacement service.
What about call quality and failover?
We engineer QoS on your firewall, dedicated voice bandwidth where needed, and automatic failover to a secondary trunk or mobile. Dual-carrier SIP plus our business internet failover designs keep Boston offices calling through ISP outages.
How long does a SIP cutover take?
Pilot trunks run within a week; full cutovers with number porting typically complete in 2–4 weeks. Your PRI stays live until SIP is tested, so rollback is instant if anything misbehaves.
Get Your Free SIP Audit
Send us your carrier bill and PBX model — we'll show the SIP savings and readiness verdict in one call.