A residential premises typically has only two phone lines installed. More phone lines may be installed at the cost of the customer.

Wireless communication technology using the radio band of the EMS (Electromagnetic Spectrum).

Sound alert to signal an incoming alert or message. See also Monophonic Ringtones and Polyphonic Ringtones. Not to be confused with a Ringing Tone, above.

Roaming refers to the ability of a wireless user to move freely, or "roam", within a building, campus or large complex while maintaining an unbroken wireless connection to the wireless local are network (WLAN). This is achieved by using a number of strategically positioned access points. As a user moves beyond the range of one access point, they are automatically handed over to the next one.

The agreement between two wireless carriers. The agreement defines roaming service capabilities and the charging structure for roaming service.

Device which directs data packet transfers along its available network paths. It examines the destination of a data packet and determines the most appropriate network point to which a data packet should be sent next. Determination of the best routing path is aided by network information received and stored by the router. A router may be a hardware or software (less common) device.

Recorded voice announcement- this is a pre-recorded announcement on the network indicating customers options, for example "telcoinabox regrets the number you have dialled is not contactable" "You cannot make outgoing calls. Please purchase a re-charge card and Dial 555" (Ding Dong) That number is not listed

Communications platform in orbit around the earth. These satellites send and receive communications signals. Satellites are very useful for their enormous coverage capabilities. There are three types, found at various heights above the earth: LEO (Low Earth Orbit, MEO (Medium Earth Orbit) and GEO (Geosynchronous Earth Orbit).

Internet connection using a satellite communications link. Two-way satellite broadband uses a satellite download link and upload link. One-way satellite broadband uses a satellite download link and a landline upload link (usually an ISDN2). Satellite broadband setup charges and running costs were subsidised in regional and rural areas through the HiBIS scheme, and are now subsidised using the Broadband Connect scheme.

Mobile phones which operate from satellites rather than land-based base stations. Coverage in remote areas is the primary use of these services, since usage costs are typically considered expensive. Also called Sat Phones. Sat Phones are often kept for emergency use in remote areas.

The size of the mobile phone or PDA handset`s screen area.

Symmetric Digital Subscriber Line (SDSL) is a Digital Subscriber Line (DSL) The main difference between ADSL and SDSL is that SDSL has the same upstream data transfer rate as downstream (symmetrical), whereas ADSL always has smaller upstream bandwidth (asymmetrical).

Also called Symmetric DSL. Download and upload speeds match, unlike ADSL. Operation is over a single copper pair, like ADSL, unlike HDSL. Traditional voice communications are unavailable, unlike ADSL, but SDSL is becoming popular for VoIP communications.

Computer hardware and software combined to `serve` information requests to its clients (PCs). Information might be data, files, emails, webpages, or other network services from client computers.

The physical address where the services are connected. A Billing Address may differ from the service address.

Monthly charge from a provider for provision of service. Call charges are additional to this charge. See also Access Fee.

The contract between a mobile service provider and customer. The `service` being supplied is connection and access to a telecommunications network. The service plan should describe all rates, charges and fees.

A company which provides telecommunications connection and service to a customer. The telecommunications service provider may be the actual carrier or a reseller of those services.

Prescribed terms and conditions which accompany a telecommunications service offer. Contains details of the service provider`s required conduct and a customer`s rights and obligations.

A SmartCard used (for mobile phones) to hold GSM encrypted security information and user information. The card holds the user`s phone number, PIN number, some or all phonebook contents and SMSs.

Switching telecommunications service provider without the customer`s knowledge or permission. This action is reversible and has been largely curtailed in Australia.

A government-run distribution portal for 1800, 13 or 1300 numbers. Often a smart number spells a mnemonic word. (eg. 1800-746-637 spells 1800-PHONES). Here are some websites which allow conversions of numbers into possible words:

Telstra product which enables landlines to have up to three distinct ringtones. By nominating up to 15 numbers per ring tone, customers can know which group a caller belongs to.

Communication of alphanumeric text messages from one mobile handset to another. (PC-to-SMS and email-to-SMS services are also available.)

SMTP - Simple Mail Transfer Protocol TCP/IP based protocol used to transfer e-mail messages over the internet. Often messages are finally retrieved from an email server using either POP or IMAP, because SMTP is not efficient at queuing emails.