BT Micro Owner’s Manual 
195 
TCP/IP  Transmission Control Protocol/Internet Protocol 
The basic protocols used on the Internet. TCP is responsible 
for dividing data up into packets for delivery and 
reassembling them at the destination, while IP is responsible 
for delivering the packets from source to destination. When 
TCP and IP are bundled with higher-level applications such 
as HTTP, FTP, Telnet, etc., TCP/IP refers to this whole suite 
of protocols. 
Telnet  An interactive, character-based program used to access a 
remote computer. While HTTP (the web protocol) and FTP 
only allow you to download files from a remote computer, 
Telnet allows you to log into and use a computer from a 
remote location. 
TFTP  Trivial File Transfer Protocol 
A protocol for file transfers, TFTP is easier to use than File 
Transfer Protocol (FTP) but not as capable or secure. 
TKIP  Temporal Key Integrity Protocol (TKIP) provides WPA with a 
data encryption function. It ensures that a unique master key is 
generated for each packet, supports message integrity and 
sequencing rules and supports re-keying mechanisms.  
triggers  Triggers are used to deal with application protocols that create 
separate sessions. Some applications, such as NetMeeting, 
open secondary connections during normal operations, for 
example, a connection to a server is established using one port, 
but data transfers are performed on a separate connection. A 
trigger tells the BT Micro to expect these secondary sessions 
and how to handle them. 
Once you set a trigger, the embedded IP address of each 
incoming packet is replaced by the correct host address so that 
NAT can translate packets to the correct destination. You can 
specify whether you want to carry out address replacement, and 
if so, whether to replace addresses on TCP packets only, UDP 
packets only, or both. 
twisted pair  The ordinary copper telephone wiring used by telephone 
companies. It contains one or more wire pairs twisted 
together to reduce inductance and noise. Each telephone 
line uses one pair. In homes, it is most often installed with 
two pairs. For Ethernet LANs, a higher grade called Category 
3 (CAT 3) is used for 10BASE-T networks, and an even 
higher grade called Category 5 (CAT 5) is used for 
100BASE-T networks. See 10BASE-T, 100BASE-T, 
Ethernet. 
unnumbered interfaces 
  An unnumbered interface is an IP interface that does not 
have a local subnet associated with it. Instead, it uses a 
router-id that serves as the source and destination address 
of packets sent to and from the router. Unlike the IP address 
of a normal interface, the router-id of an unnumbered 
interface is allowed to be the same as the IP address of 
another interface. For example, the WAN unnumbered 
interface of your BT Micro uses the same IP address of the 
LAN interface (192.168.1.1). 
  The unnumbered interface is temporary – PPP or DHCP will 
assign a ‘real’ IP address automatically. 
upstream  The direction of data transmission from the user to the 
Internet. 
USB  Universal Serial Bus 
A serial interface that lets you connect units such as printers, 
scanners, etc. to your computer by simply plugging them in.