Keyed connectors are designed to be inserted only in one direction. Keying is used as a safety feature to prevent wrong orientation/plug in which may lead to damaging the connector/circuit board
Usually T1's are terminated on an RJ48 jack. If the T1 line is provided by a telecom company, a T1 Network Interface Unit (NIU) is often installed with an RJ48 jack. A T1 NIU may also be referred to as a 'smart jack,' a device which allows remote, and on-site, loop up and testing capability, as well as indicator lights for basic fault isolation. An RJ48 jack accepts an 8-position, 8-contact (8P8C) modular connector. It's important to note that RJ48 jacks and connectors are often confused with RJ45 (Ethernet) jacks and connectors, because they may look identical, but RJ48 uses a different wiring standard and a different pinout - uses pins 1, 2, 4 & 5. However, some RJ48 jacks and connectors have a keyed notch on one side.
BNC
a lock that requires a key to be opened on both sides. common in inner cities and high crime areas.
Bnc,rj-45
No, there is no difference in b type female connectors for usb 1 or 1.1 or 2
Keyed connectors are connectors that have something on them or are shaped so they can be connected only one way. That is, so they cannot be connected incorrectly.
Almost all connectors are designed as such. PATA and SATA cables are usually keyed so that they can only be connected in one direction. SCSI connectors are shaped in a way that makes it impossible to establish a complete connection in the wrong direction.
so they fit correctly into an 8bit or 16bit slot
Jumpers
RF connectors are designed to maintain the shielding that the coaxial design offers and are typically used with coaxial cables.
designed to allow the thumb and fingers to be inserted into the rings
Memory modules will have a small notch in the bottom edge that ensures it can only be inserted into a slot one way.
SATA is designed to power hard drives and CD/DVD devices, ATX is designed for motherboards.
Light emitting diodes or LED is used to save on electricity. LED connectors are a semiconductor device designed to produce a certain wavelength and type of light.
A
Keyed Up was created in 1983.
A keyed shaft or Keyway is method, based on a machined keyway in shaft, to attach something to the shaft and associated bore. A fitted key is inserted into a slot that is machined into the shaft. Although a machined keyway does result in a weaker shaft, it has it's applications. As in a lawn mower engine shaft. Theoretically the key will give way and save the shaft if you hit something with the blade. The negatives of a keyed shaft are that it can be deformed over time and result is a loose drive.