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Dacs (Digital To Analog Converter) |
| device which converts digital pulses (data) into analog signals, so these signals can be used by analog devices such as telephones. Also known as D/A Converter |
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Dal (Dedicated Access Line) |
| A type of service often used by large companies having a telephone line going directly to the long distance company's POP/switch, thereby bypassing the local telephone company and reducing the cost per minute. A DAL uses a single channel. |
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Dal - Dedicated Access Line |
| A non-switched circuit from the customer to a carrier. |
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Data Communications |
| The process, equipment, and facilities to transmit signals from one device to another at a different location |
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Dco |
| Digital Central Office |
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Ddd - Direct Distance Dialing |
| A network consisting of all the central offices and their interconnections throughout North America. It is organized so that any telephone in North America has a unique network address and can dial any other telephone in North America without requiring an operator's assistance |
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Deactivation |
| A request to terminate service (or the process of terminating service) |
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Deaveraging |
| This means that charges in different locations may vary for the same service received. This is because it is more expensive to provide certain services in some areas than others. |
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Dedicated Access |
| A dedicated line connection between a phone or phone system and an IXC. All calls on that line are routed to the chosen IXC. |
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Dedicated Channel |
| A channel leased or purchased from the LEC to be used exclusively by the end user |
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Dedicated Line |
| A channel leased or purchased from the LEC to be used exclusively by the end user |
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Dedicated Network |
| A network in which all connections are made by dedicated lines |
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Dedicated Service |
| A communication network dedicated to a single person, group, or purpose. It may also be a specific sub part of a larger network. |
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Default Carrier |
| Your regular Dial-1 carrier. Call 1-700-555-4141 to find your default carrier. |
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Demarcation |
| A physical piece of equipment that marks where the LEC/IXC carrier's responsibilities end and the customer's responsibilities begin, in regard to the network. The demarcation point is usually located on the customer's premises |
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Demodulation |
| The process of turning analog format electrical impulses back into sound waves. 2. The process of retrieving an electrical signal from a carrier signal |
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Dial Around Numbers |
| Access codes such as 10-10-xxx numbers to override the regular long distance carrier. Dial Around may offer better rates than standard long distance calling plans but there may be monthly fees, surcharges, or minimums. |
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Dial Pulsing |
| A means of signaling consisting of regular momentary interruptions of a direct or alternating current at the sending end in which the number of interruptions corresponds to the value of the digit or character. When you dial a number, you hear a series of clicks. Each number on the keypad emits a unique sequence of clicks. Push the 4 key and you'll hear four clicks. Gets its name from the old fashioned rotary dialing telephone. |
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Dial Tone Line |
| A circuit that connects the Local Exchange Carrier’s central office to the user’s phones and equipment for business and residential services. |
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Dial Tone |
| A signal heard when the telephone handset is off the hook indicating that the central office is ready to accept and process a dialed number |
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Dial-One Access |
| The use of digit 1 preceding the 10-digit telephone number to route long-distance calls through the local network to the primary long-distance carrier pre-selected by the customer; also known as equal access |
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Dialer |
| Equipment that pulses out a standard dial protocol signal |
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Did (Direct Inward Dialing) |
| A feature of telephone systems that provides the ability for a caller outside the system to call an internal user of the system, bypassing the attendant. The digits are passed from the LEC's switching equipment to the PBX for routing |
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Did |
| (Direct-Inward-Dialing) A class of business service that enables direct dialing from outside telephones to internal station numbers via special trunks and customer equipment |
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Digital Signal |
| Transmission signal that carries information in a discontinuous stream of on/off pulses. |
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Digital Switch |
| Solid state device that routes a signal in digital format. |
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Direct Outward Dialing (Dod) |
| The ability to make calls directly form an office station without going through the PBX attendant. |
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Direct/Single Lines |
| Refers to lines from a CO or PBX that terminate on specific phones. These termini appear in the same place on every phone in that system, e.g. a direct line to the engineering group. |
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Directory Assistance Service |
| This is a service usually but not always with a fee attached, that allows you to gain access to a database of directories and listings. |
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Directory Listing |
| Appearance in the alphabetical/white pages telephone directory. There are several types of listing, including standard, bold, additional lines and a foreign listing in a directory other than the subscriber’s home directory |
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Disa (Direct Inward System Access) |
| A special capability configured for a PBX that allows a caller from any touch tone telephone outside the PBX to dial a code and access a special trunk known as a DISA line. The caller can then use the DISA line to make outgoing calls through the PBX system |
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Disconnect |
| The disassociation or release of a switched circuit between two stations. |
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Distance Sensitive |
| Cost of a call varies with the distance between origination and termination points. For example, it costs more to call Hawaii from Louisiana than to call Mississippi from Louisiana. |
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Dlr |
| Detailed Line Record |
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Dnis (Direct Number Identification Station) |
| A reference source within the switch that associates the 800 number or authorization code with the POTS telephone number. |
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Ds-0 |
| Digital Signal. A single DAL |
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Ds-1 / Ds-3 (Digital Signal Level 1 Or Level 3) |
| Digital transmission rates for time division multiplexing. DS-1 transmits voice, data and signaling at 1.544 Mbps. With the same data rate as T-1, DS-1 is equivalent to 24 DS-0 channels, or DALs, combined. DS-3 operates at 45 Mbps equivalent to 28 DS-1 facilities. SONET equivalents are VT and STS-1. |
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Dss (Direct Station Selection) |
| A piece of key system equipment that allows the attendant or answering position to know the status of individual station users, displayed via lamps. It also provides the capability to directly transfer a call to an idle station through depressing a button associated with a particular station. |
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Dtmf (Dual-Tone Multi-Frequency |
| Describes what is better known as touch-tone dialing. With DTMF signaling, when a button is depressed, a combination of two tones is sent to the distant end describing the corresponding number depressed on the touch-tone pad |
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Dual Band |
| A handset that works on both the 800 MHz cellular and the 1900 MHz PCS frequencies |
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Dual Mode |
| A handset that works on analog and digital wireless networks |
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Duplex |
| Two-way voice communication occurring simultaneously on one line |
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