• A SIP-trunking service benefits companies by:
  • Eliminating the need to invest in costly (and less capable) TDM-gateway equipment infrastructure or desktop equipment.
  • Nullifying the need to purchase equipment, such as managed-media gateway devices, to interface between IP voice and the PSTN.
  • Reducing monthly expenses, since only one connection for data and voice is needed.
  • Eliminating the need for PRI (primary rate interface)/BRI (basic rate interface) connections, lowering telephony costs.
  • Allowing companies to outsource their PSTN connectivity to a third party, reducing long-distance charges
    Providing points of presence in multiple U.S. cities so that companies can establish local numbers rather than rely on a 1-800 number.
  • Accessing the benefits of a hosted VoIP service, without discarding existing investments in a traditional phone system.


Although SIP-trunking service providers offer many options at varying costs, it is not uncommon for companies to realize instant cost savings from a relatively modest investment in SIP-based technology. Certainly, SIP requires purchasing services and products including an IP PBX, IP phones, soft clients and SIP-friendly firewalls, to name a few out-of-pocket expenses. But if deployed properly, SIP trunking can produce a healthy return on investments in less than six months.


Whenever companies attempt to mix equipment from different vendors in a unified IT environment, problems can arise. Various equipment based on the SIP protocol is certainly no exception. That’s why companies should establish best practices for interfacing a PBX implementation with an ITSP to minimize incompatibilities.

SIP trunking can also give rise to security risks. Fortunately, SIP-server and -proxy technologies can manage the flow of SIP traffic, enabling an IT manager to ensure correct routing, apply verification and authentication policies and minimize threats.

As for quality, companies would be wise to establish quality-of-service agreements with their SIP-trunking service providers before signing on the dotted line. Fortunately, measures such as the proper provisioning of links and prioritizing voice traffic can help eliminate delays and allow for proper scaling. What’s more, a network-monitoring solution can help find the best real-time traffic route for greater quality and reliability.
C . Waxer

Comtex can provide cost effective SIP trunking with IP telephone systems in New Jersey or New York. We have been specializing in the sale, installation and service of business phone systems for over 50 years.