You can find below which models compatible with SMS-30Y-NST;
|GE Healthcare :
||Avalon FM30, Avalon FM50, Avalon FM20, Avalon FM40, Avalon CL
||F2 Fetal Monitor, F6 Dual, F6 Express, AX2/3, DUS60, U50, Prime, U60, Acclarix AX4/7/8
||DP-50/40/30/20/10, DP-2200Plus, DP-2200, DP-1100Plus, Z5
It can also be compatible with other brands and models.