Datasheet

238 //
The PS/2 interface (PS/2 connection, PS/2-Port, originally Auxiliary Port) is a globally
distributed serial interface for input devices such s keyboard and mouse and less fre-
quently for other pointer devices such as trackball or graphic tablet. It is used in personal
computer, for example, but is being more and more displayed by USB.
The PS/2 interface uses a six pole Mini DIN plug. Older desktop PCs usually have two
PS/2 sockets one for the mouse (or another pointer device) and one for the keyboard.
The connections are usually colour coded, the keyboard has a violet plug or socket and
the mouse has a green plug or socket, for example (see the following illustrations).
PS/2 socket for the keyboard
PS/2 socket for the mouse / trackball
The interface is not planned for Hot Plugging, plug-in during on-going operations, for
example. Neither the protocol nor the plug-in connectors allow this Hot Plugging. It works
in many cases (more for keyboards, rather than mice), the computer or the keyboard
could be damaged in theory.
The mouse and the keyboard have different protocols although you have the same plug-in
connectors and even the same pin conguration so that the plugs should not be confused.
The manufacturers of a few current PC systems have abandoned the PS/2 interface in
favour of the Hot Plug capable USB.
PS/2-Port
Extra confusion is some caused unfortunately when the manufacturers offer these plugs
under a respective brand name such as „MultiLane iPASS“ from the company Molex,
instead ofSFF-8087.
The SAS is ideally prepared with RAID conguration for use in large storage systems:
Plug and cable specications are coordinated to Backplane use, on one hand and cheap
expanders (hubs/switches) can be used theoretically, to operate up to 16,384 devices in
one single SAS system 128 devices per expander in up to 128 expanders), on the other
hand. There are two types here, so-called edge expanders for connecting the end device
and also fan out expander as distribution points. Storage solutions with 2.5“ hard disks
and perhaps even smaller format factors are/will be possible in the future because of the
compact plugs and thin cables. This means that SAS is the ideal interface concept for
ultra compact 1U servers, blade servers and JBOD (Just a Bunch of Disks) memory arrays
with little space for cables, plugs and drives.
The following illustration gives an overview of a few connection pos-
sibilities:
Serial Attached SCSI (SAS) is a serial computer interface usually not used in the home
user area. It is the successor to the existing parallel interfaces. SAS is a point to point
connection. This means that the typical SCSI terminals as well as the award of SCSI-ID
are no longer necessary. SAS takes over the SATA plug-in connectors although SATA
end devices can be used at SAS host controllers and (generally) not vice versa.
The SAS specication denes several plug types where the ‚x‘ has to be replaced in the
SFF-xxxx standard by numbers:
SFF-8482 plug for internal connections. (left),
SFF-8484 plug for 4 channel internal connections. (right)
SFF-8487 plug for internal connections. (left),
SFF-8088 plug for 4 channel external connections. (right)
SFF-8470 plug for 4 channel external connections. Also used by Inniband.
Serial Attached SCSI