Which of the following is a telecommunication device that translates data from digital to analog form and back to digital?

A. Multiplexer

B. Modem

C. Protocol converter

D. Concentrator

A modem is a device that translates data from digital form and then back to digital for communication over analog lines.

Source: Information Systems Audit and Control Association,

Certified Information Systems Auditor 2002 review manual, Chapter 3: Technical Infrastructure and Operational Practices (page 114).