Stands for "Bits Per Second." (The "b" is lowercase because it stands for bits, not bytes.) This is the standard way of measuring how fast data moves across a network or phone system. A 56K modem can transfer 56,700 bits per second.
BPS
Meaning of BPS in English
English glossary of computer and Internet terms. Английский глоссарий компьютерных и Интернет терминов. 2012