PRI and SIP Trunking

Many businesses have an exisiting PBX and are simply in need of fast, reliable transport services. For these customers, Nexus offers both PRI and SIP Trunking services. Choosing Nexus for voice transport services allows these businesses to leverage their existing system while avoiding the headache of dealing directly with the carrier.

PRI TRUNKS: Best for businesses with onsite IT staff and still operating a legacy PBX.

SIP TRUNKS: Best for businesses with existing investments in an IP based PBX.

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  • Destination Unreachable Automatically re-route incoming calls to an alternate trunk group in case of a natural disaster or power outage.

  • Direct Inward Dial (DID) – Give your employees a direct dial number for their convenience.

  • Direct Outward Dial (DOD) – Users on the PBX can place calls directly to outside lines.

  • Business Voice Continuity – Phone calls can be routed between networks on a call-by-call basis providing seamless service during network connection issues.

  • Security – Voice services are prioritized over all other traffic and all network equipment is secured by 2 layers of authentication.

PRI vs SIP Trunking


  • PRI (Primary Rate Interface) is a physical connection to the PSTN over a dedicated line that only serves voice transmission.
  • PRI uses a circuit switched model for making voice connections between people
  • PRI has a guaranteed Quality of Service (QoS)

SIP Trunking

  • SIP (Session Initiating Protocol) Trunking is a virtual connection to the PSTN over a physical line that is often shared over your existing data connection.
  • SIP Trunking uses a packet switched model for making voice connections between people
  • SIP Trunking is typically Best Effort

If your business data is important to your success as an organization, contact us.

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