Transistor–transistor logic (TTL) is a logic family built from bipolar junction transistors. Its name signifies that transistors perform both the logic function and the amplifying function, as opposed to earlier resistor–transistor logic (RTL) and diode–transistor logic (DTL).
In electronics, a multi-transistor configuration called the Darlington configuration is a circuit consisting of two bipolar transistors with the emitter of one transistor connected to the base of the other, such that the current amplified by the first transistor is amplified further by the second one. The collectors of both transistors are connected together. This configuration has a much higher current gain than each transistor taken separately. It acts like and is often packaged as a single transistor. It was invented in 1953 by Sidney Darlington.
In electronics, emitter-coupled logic (ECL) is a high-speed integrated circuit bipolar transistor logic family. ECL uses an overdriven bipolar junction transistor (BJT) differential amplifier with single-ended input and limited emitter current to avoid the saturated region of operation and its slow turn-off behavior. As the current is steered between two legs of an emitter-coupled pair, ECL is sometimes called current-steering logic (CSL), current-mode logic (CML) or current-switch emitter-follower (CSEF) logic.
Diode–transistor logic (DTL) is a class of digital circuits that is the direct ancestor of transistor–transistor logic. It is called so because the logic gating function is performed by a diode network and the amplifying function is performed by a transistor.
The Internet Radio Linking Project, also called IRLP links amateur radio stations around the world by using Voice over IP (VoIP). Each gateway consists of a dedicated computer running custom software that is connected to both a radio and the Internet. This arrangement forms what is known as an IRLP Node. Since all end users communicate using a radio as opposed to using a computer directly, IRLP has adopted the motto "Keeping the Radio in Amateur Radio".
A push–pull amplifier is a type of electronic circuit that uses a pair of active devices that alternately supply current to, or absorb current from, a connected load. This kind of amplifier can enhance both the load capacity and switching speed.
Asterisk is a software implementation of a private branch exchange (PBX). In conjunction with suitable telephony hardware interfaces and network applications, Asterisk is used to establish and control telephone calls between telecommunication endpoints, such as customary telephone sets, destinations on the public switched telephone network (PSTN), and devices or services on voice over Internet Protocol (VoIP) networks. Its name comes from the asterisk (*) symbol for a signal used in dual-tone multi-frequency (DTMF) dialing.
A business telephone system is a multiline telephone system typically used in business environments, encompassing systems ranging in technology from the key telephone system (KTS) to the private branch exchange (PBX).
EchoLink is a computer-based Amateur Radio system distributed free of charge that allows radio amateurs to communicate with other amateur radio operators using Voice over IP (VoIP) technology on the Internet for at least part of the path between them. It was designed by Jonathan Taylor, a radio amateur with call sign K1RFD.
A remote base station is a common name for an amateur radio auxiliary station that is controlled and operated from a remote location. Most remote base stations have similar features to any other Amateur radio station but can be controlled over a direct wired connection or the internet, or by radio.
The TO-92 is a widely used style of semiconductor package mainly used for transistors. The case is often made of epoxy or plastic, and offers compact size at a very low cost.
An electronic symbol is a pictogram used to represent various electrical and electronic devices or functions, such as wires, batteries, resistors, and transistors, in a schematic diagram of an electrical or electronic circuit. These symbols are largely standardized internationally today, but may vary from country to country, or engineering discipline, based on traditional conventions.
Nortel Meridian is a private branch exchange telephone switching system. It provides advanced voice features, data connectivity, LAN communications, computer telephony integration (CTI), and information services for communication applications ranging from 60 to 80,000 lines.
Radio over Internet Protocol, or RoIP, is similar to Voice over IP (VoIP), but augments two-way radio communications rather than telephone calls. From the system point of view, it is essentially VoIP with PTT. To the user it can be implemented like any other radio network.
Integrated injection logic (IIL, I2L, or I2L) is a class of digital circuits built with multiple collector bipolar junction transistors (BJT). When introduced it had speed comparable to TTL yet was almost as low power as CMOS, making it ideal for use in VLSI (and larger) integrated circuits. The gates can be made smaller with this logic family than with CMOS because complementary transistors are not needed. Although the logic voltage levels are very close (High: 0.7V, Low: 0.2V), I2L has high noise immunity because it operates by current instead of voltage. I2L was developed in 1971 by Siegfried K. Wiedmann and Horst H. Berger who originally called it merged-transistor logic (MTL). A disadvantage of this logic family is that the gates draw power when not switching unlike with CMOS.
The RIGblaster Nomic is a radio/computer interface device used by amateur radio operators to connect their analog radio transceiver to their computer's analog sound inputs and outputs.
An open collector is a common type of output found on many integrated circuits (IC), which behaves like a switch that is either connected to ground or disconnected. Instead of outputting a signal of a specific voltage or current, the output signal is applied to the base of an internal NPN transistor whose collector is externalized (open) on a pin of the IC. The emitter of the NPN transistor is connected internally to the ground pin. If the output device is a MOSFET the output is called open drain and it functions in a similar way. For example, the I²C bus and 1-Wire bus are based on this concept.
AT&T Merlin is a corporate telephone system by American Telephone and Telegraph (AT&T) that was introduced in late 1983, when it was branded American Bell Merlin. After the breakup of AT&T in 1984, it was rebranded and later also supplied by Lucent and Avaya.
OpenBTS is a software-based GSM access point, allowing standard GSM-compatible mobile phones to be used as SIP endpoints in Voice over IP (VoIP) networks. OpenBTS is open-source software developed and maintained by Range Networks. The public release of OpenBTS is notable for being the first free-software implementation of the lower three layers of the industry-standard GSM protocol stack. It is written in C++ and released as free software under the terms of version 3 of the GNU Affero General Public License.
The ULN2003A is an array of seven NPN Darlington transistors capable of 500 mA, 50 V output. It features common-cathode flyback diodes for switching inductive loads. It can come in PDIP, SOIC, SOP or TSSOP packaging. In the same family are ULN2002A, ULN2004A, as well as ULQ2003A and ULQ2004A, designed for different logic input levels.
