Prepaid World Index Glossary
| All-A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-W-X-Y-Z |
| DA - Directory Assistance - - Phone Number Lookup
Service |
| DAL - Dedicated Access Line - - A non-switched circuit
from the customer to a carrier. |
| DDD - Direct Distance Dialing - - Any switched
telecommunication service (like 1+, 0++, etc.) that allows a call originator to
place long distance calls directly to telephones outside the local service area
without an operator. |
| DDI - Direct Dial In - - Designates a private number or
direct line which either bypasses the switchboard/PABX or is available after
hours. |
| Deactivation - - A request to terminate service (or the
process of terminating service) |
| Default Carrier - - Your regular Dial-1 carrier. Call
1-700-555-4141 to find your default carrier. |
| Dial - - To Place A Call On A Switched Network. The
term "dial" is obsolete - based on rotary dial phones and electromechanical
relay switches (which are nearly non-existent in modern telephone systems.)
Touch Tone service recognizes dual tones that are generated as each telephone
key is pressed. Where Touch Tone service is not available, telephones and
switches electronically "pulse" signals that emulate the older rotary dial
telephones. The terms "place" a call or "originate" a call are more accurate
than "dial". |
| Dial Tone - - Ready To Place/Originate A Call. When the
off hook indication is received at a central office, a dial tone signal is sent
to the originating caller on a switched network to indicate that the switch is
ready to accept a number. |
| Dialer - - Equipment that pulses out a standard dial
protocol signal. |
| Digital - - A device or method that uses discrete
variations in voltage, frequency, amplitude, location, etc. to encode, process,
or carry binary (zero or one) signals for sound, video, computer data or other
information. For example, a digital clock displays the time as discrete numeric
values, rather than angular displacement of analog hands. Digital
communications technology generally permits higher speeds of transmission with
a lower error rate than can be achieved with analog technology. When analog
signals are received and amplified at each repeater station, any noise is also
amplified. A digital signal, however, is detected and regenerated (not
amplified). Unlike amplification, any noise (less than a valid signal) is
eliminated by digital regeneration. |
| Directory Assistance - DA - - An information service
whereby operators assist customers in obtaining the telephone number(s) they
wish to call. |