HP t1000 T1000/T1010 Series Windows-based Terminal Administrator's Guide - Page 305

Modem Glossary Modular terminal Network Null modem OSD Packet PAP Parallel port Parity check 309 (Mo)dulator/(dem)odulator. Data communication equipment (DCE) devices that provide connections for computers into the public switched telephone network (PSTN). They convert (modulate) the digital signals of computers into analog signals that can be transmitted over telephone lines. A modem at the other end of the link then demodulates the signals back to digital bits. Desktop client that works with existing standard monitors. An interconnected group of nodes; a series of points, nodes, or stations connected by communications channels; the assembly of equipment through which connections are made between data stations. A cable, typically an RS-232 cable, for connecting serial ports on two computers directly, rather than via modems. Since, according to the specification, both computers should transmit on pin three of their RS-232 connectors and receive on pin two, a null modem cable needs to connect one computer's pin two to the other's pin three and vice versa. It also needs to have male connectors at both ends (again, according to the specification). On Screen Display. A menu that displays on your monitor. A group of bits (including data and call control signals) transmitted as an identifiable unit on a packet-switched network (PSN). Password Authentication Protocol. An authentication scheme used by PPP servers to validate the identity of the originator of the connection. PAP applies a two-way handshaking procedure. After the link is established the originator sends an id-password pair to the server. If authentication succeeds the server sends back an acknowledgment; otherwise it either terminates the connection or gives the originator another chance. An input/output port that allows the entire bit pattern for a single character to be sent at one time, usually used to connect a printer to a computer. The addition of non-information bits (specifically, parity bits) to make up a transmission block (a number of bits transmitted as unit) that ensures the total number of ones is always either even (even parity) or odd (odd parity). The parity check is used to detect transmission errors.