Gigaset C610-C610A IP / AUS / A31008-M2312-C401-1-7619 / Glossary.fm / 03.04.12 Glossary Glossary A ADSL Asymmetric Digital Subscriber Line Special form of DSL. ALG Application Layer Gateway NAT control mechanism of a router. Many routers with integrated NAT use ALG. ALG lets the data packets in a VoIP connection pass and adds the public IP address of the secure private network. The router's ALG should be deactivated if the VoIP provider offers a STUN server or an outbound proxy. See also: Firewall, NAT, Outbound proxy, STUN. Authentication Restriction of access to a network/service by using an ID and password to log in. Automatic ringback See Ringback when the number is busy. B Block dialling Enter the complete phone number, and correct it if necessary. Then pick up the earpiece or press the talk/speaker key to dial the phone number. Broadband Internet access See DSL. C Call divert CD Version 4, 16.09.2005 Automatic diversion (CD) of a call to a different telephone number. There are three kinds of call divert: – CDU, Call Divert Unconditional – CDB, Call Divert Busy – CDNR, Call Divert No Reply 218 Call swapping Call swapping allows you to switch between two callers or between a conference and an individual caller without allowing the waiting caller to listen to the call. Call waiting CW Network provider feature. A beep during a call indicates that another caller is waiting. You can accept or reject the second call. You can activate/deactivate the feature. CF Call Forwarding See Call divert. Client Application that requests a service from a server. Codec Coder/decoder Codec is a procedure that digitalises and compresses analogue voice before it is sent via the Internet, and decodes – i.e., translates into analogue voice – digital data when voice packets are received. There are different codecs, with differing degrees of compression, for instance. Both parties involved in the telephone connection (caller/sender and recipient) must use the same codec. This is negotiated between the sender and the recipient when establishing a connection. The choice of codec is a compromise between voice quality, transmission speed and the necessary bandwidth. A high level of compression, for example, means that the bandwidth required for each voice connection is low. However, it also means that the time needed to compress/decompress the data is greater, which increases execution time for data in the network and thus impairs voice quality. The time required increases the delay between the sender speaking and the recipient hearing what has been said.