Swipe cards are used most everywhere -- from credit cards used to make purchases to swipe cards that work as keys to enter doors and even cards that can help companies keep track of workers' time.

The Wall Street Journal looks at swipe-card readers, a technology that could change medical billing practices in the future. The paper examines units made by Companion Technologies, a subsidiary of ...

Accepting credit cards requires a payment processor like Square or Stripe, a merchant account, and hardware like POS ...