What exactly is SIP?
A SIP trunk is a Voice over IP (VoIP) connection that uses SIP to connect telephony equipment (e.g., PBXes) to the publicly switched telephone network (PSTN). SIP trunks ride over a broadband data connection and can be over-the-top, meaning companies can buy SIP trunks and broadband services from different providers or can be part of a bundled voice/data offering so providers can tweak the pipe to ensure consistent quality of service.
Is the service reliable enough for my business?
Voice over IP and SIP have evolved over the course of the last 10 years to the point that they have become a viable substitute for traditional business voice services. In fact, the vast majority of Fortune 1000 companies have been using this technology for nearly 10 years. Millions of smaller businesses have also transitioned to SIP in the last 2-3 years.
Since SIP Trunks utilize your existing broadband connection (whether it's cable, DSL or T1), the quality and reliability of the service are dependent upon the quality and the reliability of your broadband connection. Not all broadband connections are the same. Clearfly sets some minimum requirements in order for a customer to qualify for the service and provides you with an easy-to-use tool (available at https://speedtest.clearfly.net) to assess whether or not your broadband connection meets these quality requirements.
Assuming your broadband's reliability and quality meet the requirements, you can determine how much bandwidth your SIP trunks will require here.
What types/brands/makes of PBX are supported?
Clearphone UBT interfaces with the vast majority of existing business phone systems, whether they rely on traditional analog or TDM interfaces or are capable of supporting direct SIP connectivity.