RJ-11 Registered Jack-11
Telephone lines using four-wire connection.

RLL Run Length Limited
A kind of drive the encoding used, access speeds faster than the MFM method, and the same size can increase the data density of disk capacity.

RMON Remote Monitoring
A Network Management Protocol (PROTOCOL) SNMP extension of the standard, RMON 1 added a 9 MIB, RMON 2 to enhance physical layer (PHYSICAL LAYER) traffic (TRAFIC) data collection.

ROOT OS
1. UNIX system administrator account (ACCOUNT) the name of .2. Class (HIERARCHICAL) system at the highest level.