Orbtalk have a range of SIP trunk products that work with Trixbox
Designed with resellers and IT professionals in mind, Trixbox Pro is the only hybrid-hosted telephony solution on the market. With a professional service and support organization standing behind it, around-the-clock proactive monitoring, Anywhere Management™, automatic software updates, complete phone mobility, and regular configuration backups, Trixbox Pro is set to change the face of Open Source telephony forever.
The technology that drives Trixbox® Pro has been derived from Fonality's commercial IP-PBX solution which is already deployed to thousands of business sites. This means it is market proven.