A computer with radio interfacing used in remote situations where communications via wire is unavailable. Usually used to communicate with remote field equipment. PLCs with radio communication capabilities are also used in place of RTUs.
Source(s):
NIST SP 800-82 Rev. 2
under Remote Terminal Unit (RTU)
Special purpose data acquisition and control unit designed to support DCS and SCADA remote stations. RTUs are field devices often equipped with network capabilities, which can include wired and wireless radio interfaces to communicate to the supervisory controller. Sometimes PLCs are implemented as field devices to serve as RTUs; in this case, the PLC is often referred to as an RTU.
Source(s):
NIST SP 800-82 Rev. 2
under Remote Terminal Unit (RTU)