I don't own the Cosmo Communicator, but I do own its predecessor, the Gemini PDA. The 4G model of the Gemini can be used as a phone, but it's really not designed to be a phone--it has no outer screen and is essentially built around its keyboard.
I bought the WiFi-only model of the Gemini PDA knowing that I had no intention to use it as a phone; I always intended to buy the Pro1 / Pro1 X or a device like it to use as an actual phone. To that end, I installed Debian Linux on the Gemini and use it as a full Linunx UMPC.
The Gemini is now 5 years old and is definitely showing its age. I