Purple Usb Port Keyboard For Mac
USB ports on Apple keyboard are only USB1.x. Just about any USB drive over 4Gb will not have enough power to work plugged in to either of the 2 keyboard ports. I have only 3 out of about 20 that will work, and they are all old 1,2 and 4 Gb PNYs. Apple Keyboard USB ports don't have enough power. USB ports on Apple keyboard are only USB1.x. Just about any USB drive over 4Gb will not have enough power to work plugged in to either of the 2 keyboard ports. A hunch I experimented with disconnecting the extension cable and then plugging in the very short cable to the closest USB port.
The color-coded PS/2 connection ports (purple for keyboard and green for mouse) Type and data connector Production history Designer Designed 1987; 32 years ago ( 1987) Superseded, and Superseded by General specifications Hot pluggable No External Yes Cable 4 wires plus shield Pins 6 Connector Electrical Signal 5 V Max. Voltage 000000000♠5.0 ±0.5 V Max. Current 275 mA Data Data signal Serial data at 10.0–16.7 kHz with 1 start bit, 8 data bits ( first), 1 parity bit (odd), 1 stop bit, [1 ack bit (if host-to-device)] Bitrate 7–12 Max. Devices 1 or 2 Protocol Pin out. • Keyboard and mouse ports may be combined into a single port which can be used to connect both by splitter cable.
• Sometimes, keyboard Data for splitter cable. Onenote for mac printing. • Sometimes, keyboard Clock for splitter cable. The PS/2 port is a 6-pin used for connecting and to a computer system.
Its name comes from the series of, with which it was introduced in 1987. The PS/2 mouse connector generally replaced the older 'serial mouse' connector, while the PS/2 keyboard connector replaced the larger 5-pin/180° used in the design. The PS/2 keyboard port is electrically and logically identical to the IBM AT keyboard port, differing only in the type of electrical connector used.
The PS/2 platform introduced a second port with the same design as the keyboard port for use to connect a mouse; thus the PS/2-style keyboard and mouse interfaces are electrically similar and employ the same communication protocol. However, unlike the otherwise similar connector used by Apple, a given system's keyboard and mouse port may not be interchangeable since the two devices use different sets of commands and the device drivers generally are hard-coded to communicate with each device at the address of the port that is conventionally assigned to that device. (That is, keyboard drivers are written to use the first port, and mouse drivers are written to use the second port. Contents • • • • • • • • • • • • • • Communication protocol [ ] Each port implements a channel. The channel is slightly asymmetrical: it favors transmission from the input device to the computer, which is the majority case. The bidirectional IBM AT and PS/2 keyboard interface is a development of the unidirectional IBM PC keyboard interface, using the same signal lines but adding capability to send data back to the keyboard from the computer; this explains the asymmetry. The interface has two main signal lines, Data and Clock.
These are single-ended (common mode) signals driven by open-collector drivers at each end. Normally, the transmission is from the device to the computer; then, the attached peripheral device generates the Clock signal.
To transmit a byte, the device simply outputs a serial frame of data (including 8 bits of data and a parity bit) on the Data line serially as it toggles the Clock line once for each bit. The host controls the direction of communication using the Clock line; when the host pulls it low, communication from the attached device is inhibited. The host can interrupt the device by pulling Clock low while the device is transmitting; the device can detect this by Clock staying low when the device releases it to go high as the device-generated clock signal toggles. When the host pulls Clock low, the device must immediately stop transmitting and release Clock and Data to both float high. (So far, all of this is the same as the unidirectional communication protocol of the IBM PC keyboard port, though the serial frame formats differ.) The computer can use this state of the interface simply to inhibit the device from transmitting when the computer is not ready to receive. (For the IBM PC keyboard port, this was the only normal use of signalling from the computer to the keyboard. The keyboard could not be commanded to retransmit a keyboard scan code after it had been sent, since there was no reverse data channel to carry commands to the keyboard, so the only way to avoid losing scan codes when the computer was too busy to receive them was to inhibit the keyboard from sending them until the computer was ready.
This mode of operation is still an option on the IBM AT and PS/2 keyboard port.) To send a byte of data back to the keyboard, the computer pulls Clock low, waits briefly, then toggles it with a clock signal generated by the computer, while outputting a frame of bits on the Data line, one bit per Clock pulse, just as the attached device would do to transmit in the other direction. The device defers to the control of the computer over the Clock line and receives the data byte. (A keyboard normally interprets this byte as a command or a parameter byte for a preceding command.) The computer releases the Clock line when it is done. The device will not attempt to transmit to the computer until both Clock and Data have been high for a minimum period of time. Transmission from the device to the computer is favored because from the normal idle state, the device does not have to seize the channel before it can transmit—the device just begins transmitting immediately.