Business Telecommunication Systems Inc. is a provider of telecommunication technology solutions. Based in Corona, Calif., it offers customers a wide range of products, such as wireless data systems, data switching/routing equipment, voicemail, unified messaging, voice/video/data conferencing, call accounting, wireless mobility, etc. In addition, the firm provides phone system, unified messaging, data racks, server room design and more. Some of the brands represented by the company include ShoreTel, Toshiba, Avaya and Allworx. Business Telecommunication Systems Inc. has earned the Circle of Excellence and Highest Customer Satisfaction rating from ShoreTel.