According to Recommendation ITU-R SNG.770, SNG is defined as "Temporary and occasional transmission with short notice of television or sound for broadcasting purposes, using highly portable or transportable uplink earth stations…". The equipment should be capable of uplinking the video programme (or programmes) with its associated sound or sounds programme signals.
ITU-R SNG.1421 FRENCH-1999 history
1999ITU-R SNG.1421 FRENCH-1999 Common Operating Parameters to Ensure Interoperability for Transmission of Digital Television Satellite News Gathering