DTMF

Dual Tone Multi-Frequency

Another description for dual tone multi-frequency dialling (DTMF).

Dynamic IP address

A dynamic IP address is assigned to a network component automatically via DHCP. The dynamic IP address for a network component can change every time it registers or at certain time inter- vals.

See also: Static IP addressDynDNS

Dynamic DNS

Domain names and IP addresses are realised via DNS. For Dynamic IP addresses this service is now enhanced with so-called Dynamic DNS (DynDNS). This permits the use of a network component with a changing IP address as a Server on the Internet. DynDNS ensures that a service can always be addressed on the Internet under the same Domain name irrespective of the current IP address.

E

ECT

Explicit Call Transfer

Participant A calls Participant B. He puts the connection on hold and calls Participant C. Rather than connect everyone in a three-party conference, A now transfers Participant B to C and hangs up.

EEPROM

Electrically Eraseable Programmable Read Only Memory

Your phone's storage chip with fixed data (e.g.user-specific device settings made at the factory) and automatically saved data (e.g.c alls list entries).

Ethernet network

Wired LAN.

Glossary

F

Firewall

You can use a firewall to protect your network against unauthorised external access. This involves combining various measures and technologies (hard and/ or software) to control the flow of data between a private network you wish to protect and an unprotected network (e.g. the Internet).

See also: NAT.

Firmware

Device software in which basic information is saved for the functioning of a device. A new version of the firmware can be loaded into the device's memory (firmware update) to correct errors or update the device software.

Flat rate

System of billing for an Internet con- nection. The Internet provider charges a set monthly fee. There are no additional charges for the duration of the connection or number of connections.

Fragmentation

Data packets that are too big are split into smaller packets (fragments) before they are transferred. They are put together again when they reach the recipient (defragmented).

Full duplex

Data transmission mode in which data can be sent and received at the same time.

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