In telephony, the term analog is generally used to refer to pairs of copper lines which are used in a Plain Old Telephone System (POTS).
ATA (also see FXS)
Short-hand for Analog Telephone Adapter. This device permits traditional telephone devices, such as standard phones and fax machines, to function over an Internet Protocol-based network. Some examples are the Grandstream 502 and the Linksys SPA3102.
Automated Attendant System
A system which is able to direct callers to: individual people, voicemail, instructional messages, another department, etc. It often is implemented in a form in which the caller will hear a list of options and then select the corresponding number. Some systems can also recognize voice commands.
Automatic Call Distribution
Routes calls among groups of phones according to pre-specified parameters. Most often utilized in: Customer service departments, sales departments, and inbound call centers. Callers can be put in a queue and directed to the next available person.
Call Forwarding
Inbound calls, directed to a specific phone, can be forwarded to another phone in the system, or an external number.
Call Park
A user can park a call in a specific virtual parking spot and then that call can be retrieved from another phone by either dialing a code or by pressing a pre-programmed button.
Cloud-based/Hosted PBX (see also Premise-based PBX)
The VoIP telephone equipment is kept off-site and managed by your provider. Minimal equipment purchases required by the customer. Read more about it here.
A format for VoIP conversations to be encoded some examples include: G711(U-law), G722(HD), G729, and GSM (which is most commonly used in cellular applications).
Direct Inward Dial (DID)
Also known as a private line – this private phone number, allows a caller to directly reach a specific person, bypassing operator or automated attendant.
Fax Over IP (also see T.38)
Faxes can be sent over the internet by using: a T.38 gateway, an online fax service, scanning and e-mailing, or through a web portal. Read more about it here.
FXS (Foreign Exchange Station
This is another type of analog telephone adapter which permits a user to connect a traditional phone (for example, a cheap cordless phone) to their VoIP system.
A protocol which allows fax signals to be sent over IP networks. Necessary because Voice IP communications are optimized for Voice, but can cause errors with fax transmission. Read more about it here.
Find Me / Follow Me
The system can look for a specific user by calling all of his or her devices, of choice, in succession or simultaneously. (i.e. desk phone, cell phone, house phone).
Fractional T-1
This is a data transmission medium which combines multiple 64 kbps channels. It differs from a full T-1, in that a full T-1 has 24 channels, while a Fractional T-1 will have less than 24 channels.
Integrated Servcies Digital Network (ISDN)
A digital telephone network which can concurrently transfer data and voice.
Key Telephone System
A small-scale, private telephone network. Typically installed within a smaller business, this system allows individual telephones to have various functions. Some of these include: selecting outside telephone lines, placing calls on hold and calling internal phones.
Main Distribution Frame (MDF)
This is the point where local telephone wire connections are terminated.
Private Branch Exchange (PBX)
A switch implemented at a larger business where more phones are required. This is an in-house system which links local telephones together within the office; it also provides an interface for the local telephones to reach the Public Switched Telephone Network (PSTN). There may only be a few outside lines to the PSTN.
Plain Old Telephone Service (POTS)
An acronym used to refer to analog phone technology.
Premise-based PBX
The server which controls switching functions is on premises. The customer purchases all of the VoIP equipment and keeps it at their office. Read more about this here.
Primary Rate Interface (PRI)
This is the point at which the incoming trunk meets the server, which then separates the voice and data channels. It consists of 23 channels and Direct Inward Dialing (DID) is integrated.
Public Switched Telephone Network (PSTN)
This is a worldwide confluence of all of the public telecommunications networks. These networks consist of: transmission lines, switches, signaling processors and various equipment which allow connected devices to subsequently connect to each other.
Session Initiation Protocol (SIP)
An internet based protocol which supports: telephone communications, internet communications, instant messaging and other operations.
SIP Trunk
A line, or channel, which transmits and receives Voice Over IP Phone service.
A primary rate multiplexing system which merges 24 channels, all running at 64 kbps, together. Including overhead bandwidth, the stream is equal to 1.544 Mbps.
Voicemail to Email
When enabled, your voicemail messages can be sent to your email as an audio file attachment. Allows you to check your voicemail anywhere. Additionally, this feature can permit you to keep an archive of your messages.
Unified Messaging
Utilizes both voice and email messages to facilitate the forwarding, storage and retrieval of such communications. Voicemail, e-mail, faxes and messages can be checked at the same place, such as on a mobile device.
Voice over IP (VoIP, IP Telephony, and Internet telephony)
Telephony technology which is able to support voice communications over an IP network. It is the routing of voice conversations over the Internet or any other IP network.