Orbtalk have a range of SIP trunk products that work with Cisco Call Manager Express
Cisco Unified Communications Solutions for Small and Medium-Sized Businesses
Cisco Unified Communications Solutions unify voice, video, data, and mobile applications on fixed and mobile networks, enabling the human network to effectively collaborate every time, everywhere, with everyone included.
Cisco Unified Communications solutions offer presence and instant messaging capabilities that help employees reach each other on the first try, integrated messaging that combines email and voicemail, wired and wireless phones working together to extend the workspace, video and web conferencing for improved collaboration, contact center applications and more.