As has been mentioned, it WILL be a BEI encoder. All you need is the mounting type, PPR, and operating voltage. Look on the data plate on the encoder for a model number, call BEI and order one for 1/4 the price from Kone spares, or others. Always best to go to the guys that made it.

http://www.beiied.com/

It Don't mean a thing if it aint got that swing.

Cool, Free, Johnny Smith courtesy of NPR..HERE
http://www.npr.org/ramfiles/asc/asc25.smith.asx