GSM, (Global System for Mobile communications) is the phone standard supported by the Neo1973. Future phones may support other standards.
The Neo1973 is quad-band (GSM 850, 900, 1800, 1900), and will work in most countries, with the exception of some of the US, and some other parts of the world.
The GSM features (such as dialing) will be programmed via Gsmd.
You can find a full list of GSM/3GPP standards at this ETSI site (attention! more than 2000 entries).
07.07 describes the main commands used by the Gsmd software of the Openmoko system to communicate via a serial interface with the GSM subsystem of the phone.