International calling terms are many and varied terms. As a result, the terminology used when talking about international calling, international phone numbers, and international telephone service can be very confusing.
While many international calling terms are used commonly worldwide, there are also many other terms that used only in certain regions or certain countries. As a result, it is easy to get confused about things.
We ourselves still get confused when we come across too many terms like IAC, STD, SDCA, and ISD in the same sentence.
The glossary of terms below is only a very rough effort to list and define some of the more commonly used terms. The list is by no means comprehensive. And the definitions offered may not even be accurate for all countries and situations, but hopefully they are correct for most circumstances.
International Calling Terms
- Access code - A dialing code that helps the phone company identify what kind of call is being initiated. There are two main types: international access codes and national access codes. These codes are used to initiate international and domestic long-distance calls, respectively.
- Area code - A dialing code that designates a certain geographic region within a country, such as a city or state. Within each area code, local subscriber numbers are assigned to individual landline and mobile phones. Area codes may overlap each other - in other words, the same geographic region may have more than 1 applicable area. Area codes are also known as: STDs.
- Calling card - A way to buy telephone services based on pre-paid purchasing of minutes. Pre-payment is made based on advertised per minutes rates plus varying additional charges such as connection fees and maintenance fees. aka phone card.
- Cell phone - Same as mobile phone or cellular phone. Term is popular in some countries, but not as widely used worldwide as the terms 'mobile' or 'mobile phone'.
- Cellular phone - Same as mobile phone. Becoming less popular over time. 'Cellular' refers to an underlying construct of mobile telephony which is that calls are managed based on physically defined topography of 'cells' determined by the placement of transmission/reception towers.
- City code - Sometimes used as a synonym for area code - although city code can also refer to the code used for airports and other geopgraphic designations under the UN's UN/LOCODE system and/or the IATA airport coding system.
- Country code - A dialing code used to designate the country you are calling to (the destination country). 1 - 3 digits long. Also known as ISD or international subscriber dialing code.
- IDD - Acronym for international direct dialing code. A dialing code that signals you are dialing an international phone number. Same as international access code.
- International access code - A dialing code that signals you are dialing an international phone number. Same as IDD or international direct dialing code. See also access code.
- International direct dialing - Often abbreviated IDD. A dialing code that signals you are dialing an international phone number. Same as international access code.
- International subscriber dialing - Abbreviated as ISD. Same as country code, but less widely used.
- ISD - Acronym for international subscriber dialing. Same as country code, but less widely used.
- Landline phone - Refers generally to telephone service delivered to specific physical location via a fixed telecommunications network (i.e., via a wired network). The opposite of mobile phone service which allows a phone to receive calls while moving from place to place.
- LDCA - Used in India. Acronym for long distance charging area and which refers to large geographic calling areas. LDCAs are divided up into many short distance charging areas or SDCAs, each of which has a unique area code.
- Local subscriber number - The specific phone number assigned to an individual landline or mobile phone. Such number refers generally to the part of a phone number after the area code. Varies in length between countries and even within countries.
- Local virtual number - One of two main types of virtual number where the inbound caller dials to a local subscriber number. Such calls are generally free to the caller if the local number is within their area code or if the caller has flat-rate nationwide service (e.g., on many mobile plans). Any inbound calling charges are borne by the caller. The other type of virtual number is a toll-free virtual number.
- Long distance charging area - Used in India. Often abbreviated as LDCA and which refers to large geographic calling areas. LDCAs are divided up into many short distance charging areas or SDCAs, each of which has a unique area code.
- National access code - A dialing code that signals you are about to dial a domestic long distance phone call. See also access code.
- Mobile phone - A kind of phone or phone service which allows a phone to receive calls while moving from place to place. Such phone service works by sending signals wirelessly through the air via transmitters and receivers attached to cell towers. aka cellular phone, cell phone, and wireless phone.
- Phone card - Same as calling card.
- SDCA - Used in India. Acronym for short distance charging area and which refers to smaller geographic calling areas. Each SDCA has a unique code that is basically equivalent to an area code. See also LDCA and long distance charging area.
- Short distance charging area - Used in India. Often abbreviated as SDCA and which refers to smaller geographic calling areas. Each SDCA has a unique code that is basically equivalent to an area code. See also LDCA and long distance charging area.
- SIP - SIP, an acronym for 'session internet protocol' is a specific type of technology used for managing telephone calls made over the internet. In other words, SIP is a specific type of VoIP internet telephony. Click here for more information on SIP
- STD - Acronym for subscriber trunk dialing, a term used in India and elsewhere to mean area code.
- Subscriber trunk dialing - Generally abbreviated as STD. A term used in India and elsewhere to mean area code.
- Toll-free virtual number - One of two main types of virtual number where the inbound caller dials to a toll-free number from a wide long distance calling area (usually a country). Any inbound calling charges are borne by the virtual number subscriber, not the caller. The other type of virtual number is a local virtual number.
- Virtual phone number - A phone number purposefully used to forward calls to another phone number. Usually used in conjunction with a VoIP internet calling service as a way to reduce costs to inbound callers. For instance, an Indian company might buy a virtual number in the United States and then forward incoming calls to an India location so it's customers don't have to incur international calling charges. There are two main types of virtual number: local virtual number and toll-free virtual number.
- Voice over Internet Protocol - A technology for making telephone calls over the internet. See VoIP.
- VoIP - VoIP stands for Voice over Internet Protocol and refers to a relatively new technology that enables you to make telephone calls over the internet. Traditionally, phone calls have been carried over dedicated telephone switching networks - either fixed line wired networks using copper wires and fiber optics or over mobile networks using airwaves and cellular towers. With VoIP telephony, calls are routed over the same communications network that carries regular internet traffic for websites and such. Click here for more on VoIP internet telephony.
- VoIP calling card - A kind of calling card that is specifically delivered using VoIP technology. However, since most calling card companies utilize VoIP to deliver calls (even if they don't advertise as such), this may not be a terribly meaningful descriptor.
- VoIP phone - Generally used to describe a specialized type of phone that allows you to make VoIP internet calls. Certain models have dual function as a normal landline phone as well. In addition, many mobile smartphones can be configured to work with a VoIP service as well as normal mobile service.
- Wireless phone - Another term for mobile phone.
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