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Added some more info on the SP50 regarding different model types. Added some info to the JT1000 page about which radios support QCII, as well as a link to the .pdf of the Operator's Manual. While the electrical and communication layers support both hot plug and hot removal, check that your drive controller, operating system, and drivers support them. All the following situations shall not damage the device or host, and both the device and host shall resume normal TX/RX communication after any of the following events. The mechanism for powering the backplane on/off and transitioning the Host into/out of the "quiescent" state is not defined here. Prior to removal, the Host is placed into a quiescent state (not defined here) and power is removed from the backplane connector to the Device. The purpose of this section is to provide the minimum set of normative requirements necessary for a Serial ATA Host or Device to be declared as "Hot-Plug Capable". NOTE: This does not imply transparent resumption of system-level operation since data may be lost, the device may have to be re-discovered and initialized, etc. Regardless of the above definitions, the removal of a device, which is still rotating, is not recommended and should be prevented by the system designer.

Let's say both drives are hard-wired to be drive B. Now we don't have to setup them, but they both listened to the select B signal, while the motherboard would still want to send a signal to select A to select drive A. Here comes the twist! They're both hard-wired drive Bs that listen to their select B pin, but for one drive we connected the select A pin to its select B so the motherboard can control it through the select A bus. After the first drive, we twist the select cables so the drive A (that is still a hard-wired drive B) will listen to the select A controls, because we connected the select A pin to its select B pin (the only pin it listens to). They are designed so when data is connected without power, some limited drive information can still be obtained (this is mostly used in RAID and backup setups where you want to keep some disks offline to reduce wear and tear, but still need to know what's installed). I suggest "rounding" the cable afterwards, it's easier to identify which wire goes to which pin when it's still a flat ribbon.

Make sure there are NO SHORTS between any two adjacent pins of the ribbon cable joints. The drive before the twist will be drive B while the one on the end will be A. This way, there is no need to "configure" the drives which drive (A or B) are they going to be and what they should listen to. All are outputs on the floppy controller and inputs on the drives. The cable twist allows both floppy drives to be configured identically (for drive selection) when installed (for manufacturing convenience), yet operationally, can be uniquely selected as either the first drive or the second drive based on cable position. While this hack allows for the end user to not have to mess with jumpers, it also restricts the system to two floppy drives. This is totally doable, but we don't want to mess with the setting of the drives, just want to throw them into the PC case and plug in the cables. The terms control, instrumentation, and signal refer to cables that are not used to transfer power. The rest of the pins (read and write data, stepper motor control, head select, etc.) are bussed in the normal fashion, which is why the drive select pins are so critical.

It turned out to be hardwired for A and the original computer used a normal cable, but had the signals twisted on the motherboard itself! So if you plug in the power first, the drive turns on, recognizes there's no data cable, and waits for the data cable to be attached. Although it is not as effective as screened cable, it provides a very good way of reducing stray radiation and pickup. Teletype provides both, but keep in mind that the earlier revisions (with green PCB) can only support 2-3 followers reliably, and if you get dropped connections or Teletype freezing when using i2c you might want to use a powered busboard. Power must be supplied to the door lock and the Kisi Pro Controller, which work to keep the magnetic lock turned on, as stated above. But, again, the specification allows connection in any order, and should work fine in any order. Now the drive before the twist will work as a drive B listening to select B signals, while the drive after the twist will work as drive A listening to select A signals. Note that disconnecting the data first, then the power, when removing the drive will allow the drive to detect the removal, and possibly perform a few last millisecond housekeeping tasks before the power is fully removed.

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