Enterprise SIP Trunking Services

Keep your phone system, but ditch the expensive copper lines. We source flexible, scalable SIP trunks that deliver high-definition voice over your existing internet connection.

Legacy PRI Circuits

Old 23-channel copper lines. They are expensive, hard to scale (you have to buy them in blocks of 23), and physically tied to one location. If you move, you lose service.

Modern SIP Trunks

Virtual phone lines that run over the internet. You can buy exactly as many channels as you need (1 or 1,000), scale up instantly during busy seasons, and reduce costs by up to 50%.

Diagram comparing legacy PRI circuits vs flexible SIP trunking architecture

What is SIP Trunking?

SIP Trunking (Session Initiation Protocol) is the method of sending voice calls over a data connection rather than a traditional phone line. It acts as a digital bridge, connecting your existing on-premise phone system (PBX) to the Public Switched Telephone Network (PSTN) via the internet.

For businesses in Texas that have invested thousands of dollars in hardware from Avaya, Cisco, or Mitel, switching to a full Cloud UCaaS System might not make sense yet. SIP solutions offer the perfect middle ground: you keep your hardware, but modernize the connectivity behind it.

1. Elastic Scalability (“Bursting”)

One of the biggest flaws of legacy PRI lines is capacity. If you have 23 channels and a 24th customer calls, they get a busy signal. We source Elastic SIP Trunks that automatically expand to handle spikes in call volume.

This “bursting” capability ensures you never miss a sales call during peak hours, without forcing you to pay for unused capacity during the slow months.

2. Disaster Recovery & Redundancy

Physical phone lines are vulnerable. If a construction crew cuts the cable outside your building, your phones are dead. Business VoIP Trunks are location-agnostic. If your office loses power or internet, we can configure the carrier to automatically reroute calls to mobile phones or a secondary office location instantly.

3. Sourcing the Best Carrier

Not all SIP providers are equal. Call quality depends on the carrier’s underlying network (Tier 1 vs. aggregators). Alamo Telecom acts as your broker to find the right provider for your specific needs:

  • Bandwidth / Twilio: Ideal for companies with developers who want API-level control.
  • Tier 1 ISPs: Major carriers (like Verizon or Lumen) often bundle SIP with dedicated fiber for guaranteed Quality of Service (QoS).
  • Microsoft Teams Direct Routing: Specialized trunks designed to connect Microsoft Teams to the outside phone network.

Cost Comparison: PRI vs. SIP

The savings are significant. A traditional PRI circuit costs between $300 and $600 per month for 23 paths. In contrast, SIP Trunking often costs less than $15 per path (or uses a usage-based metered model).

For a company with 50 lines, switching from copper to IP-based voice can save over $10,000 annually.

Learn more about protocol standards at the SIP Forum.

Most likely. Any modern IP-PBX (system built in the last 10 years) supports SIP Trunking natively. If you have an older analog system, we can source a “VoIP Gateway” device to translate the signal.

Excellent, if your internet is stable. We highly recommend pairing SIP with Dedicated Fiber or SD-WAN to prioritize voice packets and prevent robotic-sounding calls.

Yes. We can port your entire block of DIDs (Direct Inward Dialing numbers) from your old carrier to the new SIP provider, so your employees keep their individual direct lines.

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