ABB Relion 670 Series Technical Reference Manual page 744

Section 21
Glossary
738
CBM Combined backplane module
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 megapulses per second
CMT Communication Management tool in PCM600
CO cycle Close-open cycle
Codirectional 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, two of which are used for transmitting
data in both directions and two for transmitting clock signals
CPU Central processor unit
CR Carrier receive
CRC Cyclic redundancy check
CROB Control relay output block
CS Carrier send
CT Current transformer
CVT Capacitive voltage transformer
DAR Delayed autoreclosing
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
DFC Data flow control
DFT Discrete Fourier transform
DHCP Dynamic Host Configuration Protocol
DIP-switch Small switch mounted on a printed circuit board
DI Digital input
DLLB Dead line live bus
1MRK 505 208-UEN B
Technical reference manual