Available from the Apple Mac Store, from German developer 64 Characters Telephone is a soft client VOIP SIP application based on your Mac desktop and its bloody good too. 

The client has full macOS support, which allows it to access contact information from “contacts”, allowing very fast search and dial operation.

With the application being on your Mac, especially on a MacBook it can move around with you and there’s no ugly corporate phone on the desk either.

Theres a pro feature which costs £1.99 a month via a iTunes subscription, this opens up complete call history and up to 30 simultaneous calls, and helps fund with continued app development, or you can choose the yearly option of £19.99.

Telephone and Contacts Tips

Using the application with a corporate digital system. I needed to import a list of extension names and numbers, which I did via CSV into contacts, this synced with iCloud contacts causing some confusion and a lot of work extensions in my iPhone contacts

The Fix

The fix for this is to disable contacts on your Mac for iCloud before you import or create a phone book. Then create a new Group with the “on my Mac” part of contacts when you sync 'Telephone to Contacts' you will get all contacts within the app but the work extensions don’t follow you around on your iOS devices.