In addition, Commodore made the drive's controller board smaller and having a lower chip count than the early 1541s ( which had a large PCB with dozens of TTL chips running the length of the case ).

The ZX80 was designed around readily available TTL chips ; the only proprietary technology was the firmware.

Later issue machines required the fitting of 8 dynamic RAM chips and a few TTL chips.

In 1973, LSI chips were not readily or cheaply available, so all the multiplexing and logic were done using chips that consisted of four two-input TTL NAND gates, which resulted in excessive power consumption.

A Motorola 68000-based computer with various TTL chips mounted on protoboard s.

A real-time clock built of TTL chips around 1979.

Typically, TTL chips integrate no more than a few hundred transistors each.

Standardization of the TTL levels was so ubiquitous that complex circuit boards often contained TTL chips made by many different manufacturers selected for availability and cost, compatibility being assured ; two circuit board units off the same assembly line on different successive days or weeks might have a different mix of brands of chips in the same positions on the board ; repair was possible with chips manufactured years ( sometimes over a decade ) later than original components.

Both were initially implemented via standard low-density TTL chips, each holding a 4-bit slice of the 16-bit ALU.

It was built from standard TTL chips and Programmed Array Logic chips, with four boards per CPU module.

It was built from three boards of ECL gate array chips ( with TTL pinout ).

They were introduced by RCA as CD4000 COS / MOS series in 1968, as a lower power and more versatile alternative to the 7400 series of TTL logic chips.

Eventually, the advantages of CMOS ( especially the later series such as 74HC ) edged out the older TTL chips, but at the same time ever increasing LSI techniques edged out the modular chip approach to design.

Going on these figures alone TTL logic gates are limited to perhaps 2 to 10, depending on the type of gate, while CMOS gates have DC fan-outs that are generally far higher than is likely to occur in practical circuits ( e. g. using NXP Semiconductor specifications for their HEF4000 series CMOS chips at 25 ° C and 15 V gives a fan-out of 34 thousand ).

The entire computer system is a state machine made of 74-series TTL chips.

CTC released the Datapoint 2200 using about 100 discrete TTL components ( SSI / MSI chips ) instead of a microprocessor, while Intel's single-chip design, eventually designated the Intel 8008, was finally released in April 1972.

The tracert ( traceroute ), Pathping commands are implemented by transmitting UDP datagrams with specially set IP TTL header fields, and looking for ICMP Time to live exceeded in transit ( above ) and " Destination unreachable " messages generated in response.

* The TTL field of IPv4 has been renamed to Hop Limit, reflecting the fact that routers are no longer expected to compute the time a packet has spent in a queue.

They are activated by AC control signals or DC control signals from Programmable logic controller ( PLCs ), PCs, Transistor-transistor logic ( TTL ) sources, or other microprocessor and microcontroller controls.

Nameservers may also have a TTL set for NXDOMAIN ( acknowledgment that a domain does not exist ); but they are generally short in duration ( three hours at most ).

Newer DNS methods that are part of a DR ( Disaster Recovery ) system may have some records deliberately set extremely low on TTL.

For example a 300 second TTL would help key records expire in 5 minutes to help ensure these records are flushed world wide quickly.

TTL values are " per record " and setting this value on specific records is normally honored automatically by all standard DNS systems world-wide.

Mutable ( and therefore unauthenticated ) IPv4 header fields are DSCP / TOS, ECN, Flags, Fragment Offset, TTL and Header Checksum.

Successors to the original bipolar TTL logic often are interchangeable in function with the original circuits, but with improved speed or lower power dissipation.

TTL inputs are the emitters of a multiple-emitter transistor.

TTL inputs are sometimes simply left floating to provide a logical " 1 ", though this usage is not recommended.

TTL outputs are typically restricted to narrower limits of between 0 V and 0. 4 V for a " low " and between 2. 6 V and 5 V for a " high ", providing 0. 4V of noise immunity.

Designers can combine ECL and TTL devices in the same system to achieve best overall performance and economy, but level-shifting devices are required between the two logic families.

The TTL " totem-pole " output structure often has a momentary overlap when both the upper and lower transistors are conducting, resulting in a substantial pulse of current drawn from the power supply.

V < sub > CC </ sub > and Ground are carryovers from TTL logic and that nomenclature has been retained with the introduction of the 54C / 74C line of CMOS.

The increased low output level can cause troubles when TTL logic circuits are driven.

Schottky metal – semiconductor junctions are featured in the successors to the 7400 TTL family of logic devices, the 74S, 74LS and 74ALS series, where they are employed as clamps in parallel with the collector-base junctions of the bipolar transistors to prevent their saturation, thereby greatly reducing their turn-off delays.

The 7400 series of transistor-transistor logic ( TTL ) integrated circuits are historically important as the first widespread family of TTL integrated circuit logic.

An integrated circuit made in CMOS is not a TTL chip since it uses field-effect transistors ( FETs ) and not bipolar junction transistors, but similar part numbers are retained to identify similar logic functions and electrical ( power and I / O voltage ) compatibility in the different subfamilies.

For small-scale logic, designers now use prefabricated logic gates from families of devices such as the TTL 7400 series by Texas Instruments and the CMOS 4000 series by RCA, and their more recent descendants.

Several manufacturers now supply CMOS logic equivalents with TTL-compatible input and output levels, usually bearing part numbers similar to the equivalent TTL component and with the same pinouts.

* Low-power TTL ( L ), which traded switching speed ( 33ns ) for a reduction in power consumption ( 1 mW ) ( now essentially replaced by CMOS logic )

The processor was also re-implemented using TTL components, further increasing the performance of the system.

TTL also became important because its low cost made digital techniques economically practical for tasks previously done by analog methods.

TTL inverters can also be used in crystal oscillators where their analog amplification ability is significant.

First introduced in the 500 ELX, TTL / OTF ( through the lens / off the film ) flash metering was also a feature of the 503CX, which was replaced by the 503CXi and finally the 503CW.

Regular speed TTL parts were also available for a time in the 6400 series-these had an extended industrial temperature range of − 40 C to + 85 C. While companies such as Mullard listed 6400-series compatible parts in 1970 data sheets, by 1973 there was no mention of the 6400 family in the Texas Instruments TTL Data Book.

Many parts in the CMOS HC, AC, and FC families are also offered in " T " versions ( HCT, ACT, and FCT ) which have input thresholds that are compatible with both TTL and 3. 3 V CMOS signals.

CMOS elements with TTL pin-out are also available, for example 1564 series is equivalent to 74HC.

The tick-mark here represents the omitted subfamily designator -- most commonly HC ( high-speed CMOS ), but can also be blank ( original TTL ), C ( CMOS ), LS ( low-power Schottky ), and many others.

By designing the board with as few chips as possible, he also cut down the amount of TTL ( transistor-transistor logic ) chips to 42.

Although the disc is titled Super Breakout, the game is a simulation of the original TTL Breakout, and also features an " evolved " gameplay mode.

A differential TTL signal consists of two such wires, also referenced to a system ground.

A faster logic family called Fast ( Schottky ) ( F ) was also introduced that was faster than normal Schottky TTL.

CMOS gates can also tolerate much wider voltage ranges than TTL gates because the logic thresholds are ( approximately ) proportional to power supply voltage, and not the fixed levels required by bipolar circuits.

* RS232 port is also included, but even most of Dell's employees don't know this fact and the port only supplies TTL signal level.

The FA also used the ultra-fast, bearing-mounted, honeycomb-patterned, titanium-bladed shutter and through-the-lens ( TTL ) off-the-film ( OTF ) electronic flash automation of the FE2, but added a digital liquid crystal display ( LCD ) information panel at the top left of the viewfinder to indicate the readings of the built-in, open aperture, through-the-lens ( TTL ) light meter versus the actual camera settings.

The FG was also Nippon Kogaku ’ s first amateur level SLR to have through-the-lens TTL off-the-film ( OTF ) electronic flash automation.