In digital radio, packet radio is the application of packet switching techniques to digital radio communications. Packet radio uses a packet switching protocol as opposed to circuit switching or message switching protocols to transmit digital data via a radio communication link.
On computers, a serial port is a serial communication interface through which information transfers in or out sequentially one bit at a time. This is in contrast to a parallel port, which communicates multiple bits simultaneously in parallel. Throughout most of the history of personal computers, data has been transferred through serial ports to devices such as modems, terminals, various peripherals, and directly between computers.
The Serial Line Internet Protocol (SLIP) is an encapsulation of the Internet Protocol designed to work over serial ports and router connections. It is documented in RFC 1055. On personal computers, SLIP has largely been replaced by the Point-to-Point Protocol (PPP), which is better engineered, has more features, and does not require its IP address configuration to be set before it is established. On microcontrollers, however, SLIP is still the preferred way of encapsulating IP packets, due to its very small overhead.
Loopback is the routing of electronic signals or digital data streams back to their source without intentional processing or modification. It is primarily a means of testing the communications infrastructure.
GeoPort is a serial data system used on some models of the Apple Macintosh that could be externally clocked to run at a 2 megabit per second data rate. GeoPort slightly modified the existing Mac serial port pins to allow the computer's internal DSP hardware or software to send data that, when passed to a digital-to-analog converter, emulated various devices such as modems and fax machines. GeoPort could be found on late-model 68K-based machines as well as many pre-USB Power Macintosh models and PiPPiN. Some later Macintosh models also included an internal GeoPort via an internal connector on the Communications Slot. Apple GeoPort technology is now obsolete, and modem support is typically offered through USB.
AX.25 is a data link layer protocol originally derived from layer 2 of the X.25 protocol suite and designed for use by amateur radio operators. It is used extensively on amateur packet radio networks.
Automatic Packet Reporting System (APRS) is an amateur radio-based system for real time digital communications of information of immediate value in the local area. Data can include object Global Positioning System (GPS) coordinates, weather station telemetry, text messages, announcements, queries, and other telemetry. APRS data can be displayed on a map, which can show stations, objects, tracks of moving objects, weather stations, search and rescue data, and direction finding data.
The Bell 202 modem was an early (1976) modem standard developed by the Bell System. It specifies audio frequency-shift keying (AFSK) to encode and transfer data at a rate of 1200 bits per second (bit/s), half-duplex. It has separate sets of circuits for 1200 bit/s and 300 bit/s rates. These signalling protocols, also used in third-party modems, are referred to generically as Bell 202 modulation, and any device employing it as Bell-202-compatible.
Networking hardware, also known as network equipment or computer networking devices, are electronic devices that are required for communication and interaction between devices on a computer network. Specifically, they mediate data transmission in a computer network. Units which are the last receiver or generate data are called hosts, end systems or data terminal equipment.
A terminal server connects devices with a serial port to a local area network (LAN). Products marketed as terminal servers can be very simple devices that do not offer any security functionality, such as data encryption and user authentication. The primary application scenario is to enable serial devices to access network server applications, or vice versa, where security of the data on the LAN is not generally an issue. There are also many terminal servers on the market that have highly advanced security functionality to ensure that only qualified personnel can access various servers and that any data that is transmitted across the LAN, or over the Internet, is encrypted. Usually, companies that need a terminal server with these advanced functions want to remotely control, monitor, diagnose and troubleshoot equipment over a telecommunications network.
PACTOR is a radio modulation mode used by amateur radio operators, marine radio stations, military or government users such as the US Department of Homeland Security, and radio stations in isolated areas to send and receive digital information via radio.
Q15X25 is a communications protocol for sending data over a radio link. It was designed by amateur radio operator Pawel Jalocha, SP9VRC, to be an open communications standard. Like all amateur radio communications modes, this protocol uses open transmissions which can be received and decoded by anyone with similar equipment. Q15X25 is a form of packet radio. It can be used to interconnect local VHF AX.25 packet networks over transcontinental distances. Anyone can design or adapt the open-source software to develop their own Q15X25 system.
The mini-DIN connectors are a family of multi-pin electrical connectors used in a variety of applications. Mini-DIN is similar to the larger, older DIN connector.
Telenet was an American commercial packet-switched network which went into service in 1975. It was the first FCC-licensed public data network in the United States. Various commercial and government interests paid monthly fees for dedicated lines connecting their computers and local networks to this backbone network. Free public dialup access to Telenet, for those who wished to access these systems, was provided in hundreds of cities throughout the United States.
Data Terminal Ready (DTR) is a control signal in RS-232 serial communications, transmitted from data terminal equipment (DTE), such as a computer, to data communications equipment (DCE), for example a modem, to indicate that the terminal is ready for communications and the modem may initiate a communications channel.
FX.25 is a protocol extension to the AX.25 Link Layer Protocol. FX.25 provides a Forward Error Correction (FEC) capability while maintaining legacy compatibility with non-FEC equipment. FX.25 was created by the Stensat Group in 2005, and was presented as a technical paper at the 2006 TAPR Digital Communications Conference in Tucson, AZ.
AMSAT-OSCAR 16, also known as AO-16 and PACSAT, is the in-orbit name designation of an amateur radio satellite of the OSCAR series. It was built by AMSAT and was launched on 22 January 1990 from Kourou, French Guiana on an Ariane 4 launch vehicle. It is in Sun synchronous low Earth orbit.
KISS is a protocol for communicating with a serial terminal node controller (TNC) device used for amateur radio. This allows the TNC to combine more features into a single device and standardizes communications. KISS was developed by Mike Cheponis and Phil Karn to allow transmission of AX.25 packet radio frames containing IP packets over an asynchronous serial link, for use with the KA9Q NOS program.
Fldigi is a free and open-source program which allows an ordinary computer's sound card to be used as a simple two-way data modem. The software is mostly used by amateur radio operators who connect the microphone and headphone connections of an amateur radio SSB or FM transceiver to the computer's headphone and microphone connections, respectively.
The '9600 port' is an industry-specific name given to a special connector on the back of amateur radio HF, VHF, and UHF transceivers. It is used for connecting a packet radio modem or any other type of data-modem which uses audio tones to convey data.
