DASS Digital Access Signalling System. A UK-only public network standard developed by BT and its suppliers. Current version is DASS2 It is in the process of being replaced by the European standard Q931.
DC5 This is an analogue signalling protocol used on leased lines for private networking. It uses direct current and so is more restricted in the area it can cover than AC15.
DCC Delta Channel Controller
DDI Direct Dialling In allows callers to ring specific extensions and departments and bypassing the main switchboard. This can be an extremely useful feature and requires ISDN with blocks of DDI numbers.
DECT Stands for digitally enhanced cordless telephony. It is the European standard for cordless telephones. DECT handsets can be used as extensions to some modern telephone systems as well as stand alone cordless telephones.
Dial This used to be round and is now a key pad of the 10 digits
DID Direct Inward Dialling is a less sophisticated version of DDI utilising dedicated exchange lines for each extension. It does offer some of the advantages of DDI and at a lower cost on smaller systems but it lacks the flexibility.
DIGITAL Digital is a method of transmitting a binary code (the same code used by computers) over the telephone network. The main advantages over analogue technology in that it is resistant to electromagnetic interference and difficult to bug. Digital makes it possible to integrate voice and data over telecommunication lines.
DIRECT EXTENSION ANSWERING Direct extension answering allows specific extensions to answer incoming calls even if you have a the central operator. This can be useful when the volume of traffic is too much for one operator to handle.
DISA Direct Inward System Access allows callers to dial in, hear a tone and then dial the specific extension number they require. There are different levels of DISA available, some systems allow a recorded message to be played guiding the caller through the call. For example, callers might be asked to dial ‘1’ for service, ‘2’ for sales etc. Calls can always be diverted to an operator by the caller or if say the extension is busy or remains unanswered. It is sometimes possible to have optional authorisation codes or PIN numbers to limit access to DISA lines, this can act as extra security for companies using remote access with networking applications, making it harder for hackers getting computer systems attached to phone lines.
DISTINCTIVE RINGING Distinctive ringing distinguishes between internal and external calls. It is also referred to as external/internal line identity.
DLI Digital Link Interface.
DN Directory Number. The number listed to be dialled by customers for connection to a particular answering point. Each agent position or telephone within a network may have a unique directory number. DND Do Not Disturb stops individual handsets from receiving calls, paging announcements, ‘camp-on’ ringing. It can be interrupted by handsets with executive intrusion.
DONGLE A software protection device.
DOOR LOCKING This feature enables your telephone system to be used as door entry system so you can speak to visitors before you decide to let them in. Peripheral equipment may be required.
DPNSS The Digital Private Network Signalling System is a UK standard signalling system for use between telephone systems . It allows the transmission of voice, data and images over leased lines.
DSL Digital Subscriber Line
DSS Direct Station Select. A button on a terminal which can be used to directly dial a person or extension associated with that button.
DSS CONSOLE Direct Station Select Consoles to be attached to some handsets enabling them to act as operators. These consoles give you a visual information as to the status of extensions and whether they are busy. Direct station selection also makes it easier to transfer calls.
DTMF touch-tone phones have numbers 0 to 9 and have a ‘#’ key and a ‘*’ key. They Dual Tone Multiple Frequency is the method by which telephones carry signals. DTMF or can be used for basic interaction with computers and voicemail systems (when ordering cinema tickets for instance) and provide faster connection when dialling out.
DUAL AUDIO PATHS These lets you to have two lines into one handset making it possible to carry out other functions.
DUAL COLOUR LED’s This is when one LED can indicate the status of a line by changing colour, usually green means the station is free and red indicates that the station is busy.
DUAL SPEECH PATHS This is the same as Dual audio path with the added functionality of allowing two voice lines to a single extension. It is necessary if you are attaching your handset to a computer terminal and would like to use both at the same time.
