splitterless | A type of DSL installation where no splitter is installed, |
| saving the cost of a service call by the telephone compa- |
| ny. Instead, each jack in the home carries both voice and |
| data, requiring a microfilter for each telephone to prevent |
| interference from the data signal. ADSL is usually split- |
| terless; if you are unsure if your installation has a splitter, |
| ask your DSL provider. See also splitter, microfilter. |
subnet | A subnet is a portion of a network. The subnet is dis- |
| tinguished from the larger network by a subnet mask |
| which selects some of the computers of the network |
| and excludes all others. The subnet’s computers remain |
| physically connected to the rest of the parent network, |
| but they are treated as though they were on a separate |
| network. See also network mask. |
subnet mask | A mask that defines a subnet. See also network mask. |
TCP | See TCP/IP. |
TCP/IP | Transmission Control Protocol/Internet Protocol The basic |
| protocols used on the Internet. TCP is responsible for di- |
| viding data up into packets for delivery and reassembling |
| them at the destination, while IP is responsible for deliv- |
| ering the packets from source to destination. When TCP |
| and IP are bundled with |
| HTTP, FTP, Telnet, etc., TCP/IP refers to this whole suite of |
| protocols. |
Telnet | An interactive, |
| 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. |
TTL | Time To Live A field in an IP packet that limits the life |
| span of that packet. Originally meant as a time duration, |
| the TTL is usually represented instead as a maximum hop |
| count; each router that receives a packet decrements this |
| field by one. When the TTL reaches zero, the packet is |
| discarded. |
twisted pair | The ordinary copper telephone wiring long used by tel- |
| ephone 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 |
| |
upstream | The direction of data transmission from the user to the |
YML754 Rev1 | NB5Plus4/W User Guide |
www.netcomm.com.au | 105 |