Instruction manual

ABBREVIATIONS AND ACRONYMS
CDM Channel Division Multiplexing
CDOS Customer-Dialed and Operator-Serviced
CDR Call Detail Recording
CDRR Call Detail Recording and Reporting
CDRU Call Detail Recording Utility
CEM Channel Expansion Multiplex
CI Clock Input
CMDR Centralized Message Detail Recorder
CMS Call Management System
CO Central Office
COR Class of Restriction
COS Class of Service
CPE Customer Premises Equipment
CPN/BN Calling Party Number/Billing Number
CPS Characters Per Second
CPTR Call Progress Tone Receiver
CRC Cyclical Redundancy Checking
CSA Canadian Safety Association
CSD Customer Service Document
CSM Centralized System Management
CSS Center Stage Switch
CSU Channel Service Unit
DC Direct Current
DCE Data Communications Equipment
DCP Digital Communications Protocol
DCS Distributed Communications System
DDC Direct Department Calling
DDD Direct Distance Dialing
DID Direct Inward Dialing
DIOD Direct Inward/Outward Dialing
DLC Data Line Circuit
DLDM Data Line Data Module
DMI Digital Multiplexed Interface
DND Do Not Disturb
DNIS Dialed Number Identification Service
DOD Direct Outward Dialing
DOSS Delivery Operations Support System
DS1 Data Services Level 1
DSI Digital Service Interface
DSU Data Service Unit
DTDM Digital Terminal Data Module
DTE Data Terminal Equipment
DTGS Direct Trunk Group Select
DTMF Dual Tone Multifrequency
DXS Direct Extension Selection
E&M Ear and Mouth (Receive and Transmit)
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