"RS" in communication standards RS232 and RS485 stands for "Recommended Standard". But what information does "232" or "422" or "485" convey in the name? What naming convention is used for numbers succeeding the letters "RS" when naming the RS standards?
The numbers themselves have no meaning. For example while EIA232 specifies the electrical characteristics of a digital serial communications system, EIA222 specifies standards for antenna masts and RS225 is a standard for RF connectors.
Wikipedia has an incomplete list of popular RS/EIA standards: https://en.wikipedia.org/wiki/EIA_standards
It signifies nothing; it's part of a sequential list of EIA standards: -