ABB RET670 Installation And Commissioning Manual page 232

Section 17
Glossary
226
CCITT Consultative Committee for International Telegraph and
Telephony. A United Nations sponsored standards body
within the International Telecommunications Union.
CCM CAN carrier module
CCVT Capacitive Coupled Voltage Transformer
Class C Protection Current Transformer class as per IEEE/ ANSI
CMPPS Combined mega pulses per second
CO cycle Close-open cycle
Co-directional Way of transmitting G.703 over a balanced line. Involves
two twisted pairs making it possible to transmit information
in both directions
COMTRADE Standard format according to IEC 60255-24
Contra-directional Way of transmitting G.703 over a balanced line. Involves
four twisted pairs of with two are used for transmitting data
in both directions, and two pairs for transmitting clock signals
CPU Central processor unit
CR Carrier receive
CRC Cyclic redundancy check
CS Carrier send
CT Current transformer
CVT Capacitive voltage transformer
DAR Delayed auto-reclosing
DARPA Defense Advanced Research Projects Agency (The US
developer of the TCP/IP protocol etc.)
DBDL Dead bus dead line
DBLL Dead bus live line
DC Direct current
DFT Discrete Fourier transform
DIP-switch Small switch mounted on a printed circuit board
DLLB Dead line live bus
DNP Distributed Network Protocol as per IEEE/ANSI Std.
1379-2000
DR Disturbance recorder
DRAM Dynamic random access memory
DRH Disturbance report handler
DSP Digital signal processor
DTT Direct transfer trip scheme
1MRK 504 088-UEN C
Installation and commissioning manual