
Appendix
127
Stimulus
Key sequence entered via a telephone keypad to start or activate certain
features.
Subnet mask
A subnet mask is a string of 4 dot separated figures having the same structure
as an IP address. You may receive it from your internet service provider
together with TCP/IP-information. A subnet mask enables you to define IP
addresses limited to a certain network (in contrast to valid IP addresses being
recognized all over the internet).
Switch
Device to connect a number of computers to a network. Today switches have
replaced so called hubs.
TCP/IP
Transmission Control Protocol / Internet Protocol. Standard protocol for
transferring data on the internet.
UPS
Uninterruptible power supply. A device that enables operation of your
telephone system even in case of power failure for a limited time.
Dial tone
There is an internal and an external (exchange) dial tone.
WAN
Wide-Area-Network. Combinations of different LANs via fast long distance
lines are called WAN. The best-known example is the internet.
Access control
Protective measure to keep unauthorised persons from accessing your own
network.