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

The maximum value of this current is about 1. 6 mA for a standard TTL gate.

* High-speed TTL ( H ), with faster switching than standard TTL ( 6ns ) but significantly higher power dissipation ( 22 mW )

Before the advent of VLSI devices, TTL integrated circuits were a standard method of construction for the processors of mini-computer and mainframe processors ; such as the DEC VAX and Data General Eclipse, and for equipment such as machine tool numerical controls, printers and video display terminals.

The final metering prism for the Nikon F, the Photomic FTn, introduced in 1968, provided 60 % center-weighted TTL which became the standard metering pattern for Nikon cameras for decades afterwards.

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.

The processor, memory, floppy controller, PIA, ACIA and EPROMs were interconnected with standard TTL devices.

The TTL logic gate, which was the electronics industry standard for two decades, was invented by TRW's James L. Buie in 1961.

Unlike the TTL connectors used in the early days of home computing and game consoles ( most notably the DE-9 connector originally found on the Atari VCS, which was the de facto standard on other systems ) the game port is analog rather than digital, relying on some form of analog-to-digital converter ( ADC ) to interpret joystick movements.

* CPU: 8-bit, made from standard TTL components.

** 74-the " standard TTL " logic family had no letters between the " 74 " and the specific part number.

Although the 7400 series was the first de facto industry standard TTL logic family to be second-sourced by several semiconductor companies, there were earlier TTL logic families such as the Sylvania SUHL ( Sylvania Universal High-level Logic ) family, Motorola MC4000 MTTL family ( not to be confused with RCA CD4000 CMOS ), the National Semiconductor DM8000 family, Fairchild 9300 series, and the Signetics 8200 family.

The 25120 required a 6. 3 VAC V < sub > ff </ sub > ( vacuum tube filament ) supply, a + 10 V < sub > cc </ sub > ( double the V < sub > cc </ sub > of standard TTL logic of the day ), and V < sub > dd </ sub > of zero volts ( i. e. ground ), ± 2 %.

The HP 9810, 9820 and 9830 desktop computers used a slow, serialized TTL version of the 2116 CPU, although they did not ultimately use any of the operating system or application software, instead relying on user-friendly ROM-based interpreters such as BASIC which worked when powered up and integrated keyboards and displays rather than disks or standard terminals.

The Roombas with an interface ( 400 series models from after October 2005 and newer series like 500 and 700 ) come with a Mini-DIN connector supporting a TTL serial interface, which is incompatible with standard PC / Mac serial ports and cables, both electrically and physically.

Differential TTL is a type of binary electrical signaling based on the TTL ( transistor-transistor logic ) standard.

Differential TTL signaling was used in the Serial Storage Architecture ( SSA ) standard devised by IBM, but this is mostly obsolete.

Since the transistors of a standard TTL gate are saturated switches, minority carrier storage time in each junction limits the switching speed of the device.

Because of the incompatibility of the CD4000 series of chips with the previous TTL family, a new standard emerged which combined the best of the TTL family with the advantages of the CD4000 family.

The time for which a resolver caches a DNS response is determined by a value called the time to live ( TTL ) associated with every record.

The TTL is set by the administrator of the DNS server handing out the authoritative response.

As a noteworthy consequence of this distributed and caching architecture, changes to DNS records do not propagate throughout the network immediately, but require all caches to expire and refresh after the TTL.

An older common TTL value for DNS was 86400 seconds, which is 24 hours.

A TTL value of 86400 would mean that, if a DNS record was changed on the authoritative nameserver, DNS servers around the world could still be showing the old value from their cache for up to 24 hours after the change.

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

To limit the impact of DNS poisoning typically a TTL of 0 is used.

For example, every device ( such as an intermediate router ) forwarding an IP datagram first decrements the time to live ( TTL ) field in the IP header by one.

Therefore, IPv6 routers do not need to recompute a checksum when header fields ( such as the time to live ( TTL ) or hop count ) change.

* 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.

* an 8-bit TTL ( time to live ) field.

In theory, under IPv4, time to live is measured in seconds, although every host that passes the datagram must reduce the TTL by at least one unit.

When a caching ( recursive ) nameserver queries the authoritative nameserver for a resource record, it will cache that record for the time ( in seconds ) specified by the TTL.

* Schottky TTL ( S ), introduced in 1969, which used Schottky diode clamps at gate inputs to prevent charge storage and improve switching time.

Waiting for a trigger, starting the ADC, looking up the time, waiting for the ADC to finish, move value to RAM, switch multiplexer, get TTL input, let DAC proceed with voltage ramp.

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.

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.

At the time the 7400 series was being made, some European manufacturers ( that traditionally followed the Pro Electron naming convention ) such as Philips / Mullard produced a series of TTL integrated circuits with part names beginning FJ.

* 40, 42, 44, 48: Schottky TTL, 4 Top of stack registers, 105 ns microinstruction cycle time → 9. 5 MHz

Other accessories for the FM3A include the Nikon MD-12 motor drive ( automatic film advance up to 3. 2 frames per second ), as well as the Nikon MF-16 databack ( sequential numbering, time or date stamping on the film ), and the various compatible Nikon TTL flashes ( SB-15, SB-16b, SB-20, etc.

a fast discriminator senses the steep onset of the avalanche current across a 50 Ω resistor and provides a digital ( CMOS, TTL, ECL, NIM ) output pulse, synchronous with the photon arrival time.

A RouteRequest carries the source identifier ( SrcID ), the destination identifier ( DestID ), the source sequence number ( SrcSeqNum ), the destination sequence number ( DestSeqNum ), the broadcast identifier ( BcastID ), and the time to live ( TTL ) field.

Each node, upon receiving a RouteRequest packet, rebroadcasts the packet to its neighbors if it has not forwarded it already, provided that the node is not the destination node and that the packet ’ s time to live ( TTL ) counter has not been exceeded.

Ethernet does not have a time to live ( TTL ) field in its frame header, so loop avoidance must be arranged by other means.

$ TTL 1h ; default expiration time of all resource records without their own TTL value