Yes, MODEMS is a Scrabble word!

Letter values in Scrabble US: M 3, O 1, D 2, E 1, M 3, S 1.

Is it a valid word?

MODEMS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

(from a combination of MOdulate and DEModulate) electronic equipment consisting of a device used to connect computers by a telephone line