Telecom Service

Of Atlanta


SIP Trunking

SIP trunking is a logical circuit connection offered by an Internet Telephony Service Provider (ITSP). It connects your on-premise phone system (PBX) to the existing telephone system infrastructure (Public Switched Telephone Network) over high-speed Internet access. SIP Trunking is the replacement for expensive ISDN-PRI digital trunk connections. If your company's already made the investment in high-speed Internet access, TSA can deliver SIP trunks to you today!!


SIP trunks offer you significant cost-savings and eliminates your need for expensive Primary Rate Interfaces (PRIs) entirely while simplifying your Unified Communications (UC) environment. As your main office expands and you open new locations, our

On Demand Scalability allows for the addition of logical lines via remote enabling. Now your home-based workers can be added on demand.

Different Methods of Implementing SIP Trunking

Example 1. SIP Trunking connectivity to your Legacy TDM PBX is with an Adtran Integrated Business Gateway with a  T-1 or PRI interface.

The IAD is behind your firewall and SIP traffic ports are forwarded thru the firewall to the internal network interface of the IAD. The IAD offers

a single-box solution for hybrid IP/TDM and analog voice networks providing SIP trunking for existing PBX and Key systems. The integral SIP

gateway converts analog phones, trunks, and TDM-based PBX connections to IP for a simple network migration.



Example 2. Direct SIP Connectivity. The customer forwards SIP ports from their firewall to the SIP-ready PBX. No IAD is required. Only a

limited number of VOIP systems support a direct SIP trunking connection. Digium/Switchvox supports a direct SIP trunking connection.  

Example 3: SIP Connectivity with SIP Border Controller (SBC). A SBC provides SIP traffic normalization thru your firewall. In some cases, the

SBC includes a built-in firewall for SIP traffic normalization.