The subway and bus are the way most popular way when people are in travel, so the convenience of taking subway buses definitely reflects the convenience of a city. In this regard, China has provide scanner for scanning qr code to entering the metro or bus in many cities ,Some can scan the code (the subway also needs a special gate), some can pay thought by bar code 

Shenzhen Rakinda RD4500 recognition sensor equipment embedded in scanner engine on Gate machines and ticket machines , professional reading mobile phone screen reader, the use of international level microprocessors, so if you has less change when no need to change to the Customer Service Center,it easy to solve people just take out the phone ,RD4500R Scanner module which is specialized in Smart cashless, it is good for mobile screen and very flexible for scanning the barcode ,RAKINDA is a company committed to the development up to bar code technology at the core of the automatic identification system integration organizations.

RAKINDA is a company committed to the development up to bar code technology at the core of the automatic identification system integration organizations, enjoyed several years of industry experience and excellent reputation, in Shenzhen and Hong Kong branches, and has a very skillful, experienced, innovative R & D and after-sales technical support service team. Rakinda Group, the manufacturer of barcode scanner module, was established in 2000. We have offices in Guangzhou, Shenzhen, Hongkong, Xiamen, Suzhou and Beijing. And we have been supplying the barcode scanner module for Walmart, Carrefour and Foxconn etc.