DOD
DOD refers to direct outward dialing. If an employee can dial and reach an outside number without internal operator intervention, then the company has implemented DOD. In the past, when less-sophisticated telephone systems were available, it was not uncommon for a company to route all of its outbound calls through an internal operator. The operator’s responsibility was both to screen calls (no, you may not call Australia from that telephone) and to route the calls over the appropriate facilities (e.g., the right WATS lineāsee below). With the advent of modern PBXs and Centrex, such limitations can be programmed, if desired, on a telephone by telephone, or even user-by-user basis, eliminating the requirement to involve an operator in outbound calls. DOD is a term not often used these days because few companies consider not providing it.
This introduction is meant to teach you about the functions and technology of a Central Office.
Sound
Analog to Digital
Bandwidth
Facilities Network
Traffic Networks
Public Switched
The Telephone Network
A Topology of Connection
Network Hierarchy (pre 1984)
Network Hierarchy (post 1984)
North American Numbering Plan
International Numbering
The Subscriber Extension
Private Networks
Hybrid Networks
Local Access and Transport Areas
Wiring Connections: Hooking Things Up
Types of Communication
Signaling (SS7)
Lines Vs. Trunks
Loop Start
Calling Procedures
Ground Start
E&M Signaling
Foreign Exchange Signal
DID
DOD
FX
OPX
Wats