SIP Trunks & SIP Trunking for Montana Businesses
Big Sky Telecom's SIP trunking service connects your existing phone system to the internet, giving you the full power of VoIP phone service without replacing your hardware. Our SIP trunk lines are built for reliability, supporting businesses across Missoula, Helena, Kalispell, and all of Western Montana.
Your PBX. Our Network. The World's PSTN.
SIP trunks replace your legacy PRI or analog POTS lines with a standards-based IP connection - keeping your existing PBX investment while adding cloud-grade reliability and scale.
Automatic Failover - No Manual Steps
Every SIP trunk account includes a primary and secondary endpoint. Heartbeat monitoring detects failures in under 30 seconds and re-routes traffic automatically - before most users even notice.
Primary Route Active
All calls route through your primary SIP trunk endpoint on our geo-redundant Montana infrastructure.
Heartbeat Monitoring
Our platform sends SIP OPTIONS pings every 30 seconds. If responses stop, failover triggers automatically.
Automatic Re-Route
Traffic instantly shifts to your secondary endpoint or a pre-configured overflow destination - no human action required.
Alert & Restore
Your team is notified via email or SMS. When the primary route recovers, traffic shifts back automatically.
Everything a Modern SIP Trunk Should Do
Elastic channels, strong security, number portability, and self-service management - without the PRI minimums or long-term commitments.
Elastic Channel Capacity
Start with as few as 1 concurrent channel and scale to hundreds with no hardware procurement. Add or reduce channels the same day - capacity follows your business, not the other way around.
Automatic Failover
Primary and secondary SIP trunk endpoints are provisioned automatically. If the primary route fails, calls automatically failover to the backup within seconds - no manual intervention required.
SRTP / TLS Encryption
All SIP signaling is protected with TLS and media streams are encrypted with SRTP. Protect sensitive business calls in transit without additional configuration.
Inbound DID Routing
Route inbound calls from any of your DID numbers to specific extensions, ring groups, IVRs, or queues on your PBX. Full E.164 number control from the portal.
Outbound Caller ID Control
Present any verified DID on outbound calls. Set default outbound caller ID per trunk group or per extension - essential for businesses with multiple brands or locations.
CDR & Usage Reporting
Full call detail records for every inbound and outbound leg - timestamp, duration, destination, channel consumed. Export to CSV for billing reconciliation.
Multiple Trunk Groups
Segment traffic by department, location, or call type across separate trunk groups. Assign dedicated channels to your sales team, support queue, or fax lines.
Number Porting
Bring your existing geographic, toll-free, or fax numbers. Our porting team manages the entire process - submit the LOA and we handle the rest.
Self-Service Portal
Provision new trunks, adjust capacity, update routing rules, and pull CDRs from any browser - no ticket required for routine changes.
Compatible With Your Existing Setup
We support the full range of standard SIP codecs - from legacy G.711 for maximum PBX compatibility to G.722 HD voice and Opus for wideband quality.
Codec negotiation happens automatically during SIP handshake. Preferred codec order is configurable per trunk group.
Works With What You Already Have
Any RFC 3261-compliant PBX or UC platform works out of the box. We provide tested configuration guides for the most common systems - no guesswork required.
Scale From 1 Channel to 1,000+ - No Hardware
Traditional PRI lines lock you into increments of 23 channels with months of lead time. SIP trunks let you add or reduce concurrent channels the same day - pay only for what you use.
Simple, Scalable SIP Trunk Pricing
Start with one channel and scale up as your business grows. No hardware required - works with your existing PBX.
Pay Per Channel
For businesses with predictable call volume.
- No monthly channel fee
- Per-minute outbound rates
- Inbound calls billed per minute
- Up to 10 concurrent channels
- 1 DID number included
- Self-service portal access
- Standard support
Metered Bundle
Best value for growing businesses.
- Flat monthly per-channel fee
- Unlimited inbound calls
- Low per-minute outbound rates
- Up to 500 concurrent channels
- 1 DID per channel included
- Primary + secondary failover
- SRTP / TLS encryption
- CDR reporting & export
- Priority support
Unlimited Trunk
For high-volume and enterprise operations.
- Unlimited inbound minutes
- Pooled outbound minute blocks
- 500+ concurrent channels
- Geo-redundant dual-site trunks
- Custom SLA agreement
- Dedicated account manager
- On-site or remote configuration
- Priority 24/7 support
Optional Add-Ons
All SIP trunk plans include free number porting, E911 compliance, and Missoula-based technical support.
What Our Customers Say
Montana businesses that made the switch from PRI to SIP.
"We moved our 3CX system off our old ISDN lines to Big Sky SIP trunks and cut our monthly telecom bill by 40%. The configuration guide they sent had us up in an afternoon."
"The failover just works. We had a WAN event last quarter and calls automatically rerouted through the secondary trunk without anyone noticing. That's exactly what you pay for."
Common Questions
Everything you need to know before migrating from PRI.
What is SIP Trunking?
SIP trunking is a way to deliver business phone service over the internet using your existing PBX hardware. Instead of traditional analog phone lines, SIP trunks use your internet connection to carry voice calls — reducing costs and adding flexibility.
How many business phone lines do I need?
Most small businesses need 1 SIP trunk channel per 3–5 employees actively on calls at once. We'll help you right-size your business phone line count during your free consultation.
Can I use SIP trunks with my current PBX?
Yes. Our SIP trunks are compatible with most on-premise and hosted PBX systems. Book a call to verify compatibility with your setup.
What is a SIP trunk and do I need one?
A SIP trunk replaces traditional phone lines (POTS or PRI) with an internet-based connection. If you have an existing PBX system you want to keep but want to eliminate expensive phone company line charges, SIP trunking is the right solution.
What happens if my internet goes down?
We configure automatic failover to a backup number or mobile line of your choice. Calls route automatically without any manual intervention.
Can I keep my existing phone numbers?
Yes. We port your current numbers at no charge. Your customers keep calling the same numbers - nothing changes on their end.
Is E911 supported?
Yes. All our SIP trunks include E911 compliance with registered physical addresses for emergency routing.
How long does setup take?
Most SIP trunk deployments are complete within 48 hours. Number porting typically takes 5-10 business days depending on your current carrier.
Ready to Replace Your PRI Lines?
Our team will review your current telecom setup, recommend the right channel count, and handle number porting from start to finish. Most migrations complete within two weeks.