Editing SATA (section)

=== Data connector <span class="anchor" id="DATACONN"></span> ===
{{See also|SATA Express#CONNECTORS|l1=SATA Express connectors}}

{| class="wikitable" style="float:right; margin-left:1em; margin-right:0; margin-top:0;"
|+ Standard connector, data segment, host side signal naming
|-
! colspan="2"| Pin # !! Mating !! Function
|-
| style="background:black;" |
| 1
| style="text-align:left;" | 1st
| Ground
|-
| rowspan="2" style="background:blue;" |
| 2
| style="text-align:right;" | 2nd
| A+ (transmit)
|-
| 3
| style="text-align:right;" | 2nd
| A− (transmit)
|-
| style="background:black;" |
| 4
| style="text-align:left;" | 1st
| Ground
|-
| rowspan="2" style="background:blue;" |
| 5
| style="text-align:right;" | 2nd
| B− (receive)
|-
| 6
| style="text-align:right;" | 2nd
| B+ (receive)
|-
| style="background:black;" |
| 7
| style="text-align:left;"| 1st
| Ground
|-
| colspan="3" style="text-align:center;" | &nbsp;— || Coding notch
|}

The SATA standard defines a data cable with seven conductors (three grounds and four active data lines in two pairs) and 8&nbsp;mm wide wafer connectors on each end. SATA cables can have lengths up to {{convert|1|m|ft|sp=us}}, and connect one motherboard socket to one hard drive. PATA [[ribbon cable]]s, in comparison, connect one motherboard socket to one or two hard drives, carry either 40 or 80 wires, and are limited to {{convert|45|cm|in|sp=us}} in length by the PATA specification; however, cables up to {{convert|90|cm|in|sp=us}} are readily available. Thus, SATA connectors and cables are easier to fit in closed spaces and reduce obstructions to [[air cooling]]. Some cables even include a locking feature, whereby a small (usually metal) spring holds the plug in the socket.

SATA connectors may be straight, upward-angled, downward-angled, leftward-angled, or rightward-angled. Angled connectors allow lower-profile connections. Downward-angled connectors lead the cable immediately away from the drive, on the circuit-board side. Upward-angled connectors lead the cable across the drive towards its top.

One of the problems associated with the transmission of data at high speed over electrical connections is described as ''noise'', which is due to electrical coupling between data circuits and other circuits. As a result, the data circuits can both affect other circuits and be affected by them. Designers use a number of techniques to reduce the undesirable effects of such unintentional coupling. One such technique used in SATA links is [[differential signaling]]. This is an enhancement over PATA, which uses [[single-ended signaling]]. The use of fully shielded, dual [[coaxial cabling|coax]] conductors, with multiple ground connections, for each differential pair<ref>Serial ATA Revision 3.0 ''6.1.8 Internal single-lane cable''</ref> improves isolation between the channels and reduces the chances of lost data in difficult electrical environments.

<gallery widths="250" heights="150">
File:SATA-cable.jpg|SATA data cable
File:2.5-inch SATA drive on top of a 3.5-inch SATA drive, close-up of data and power connectors.jpg|SATA connectors on 2.5 and 3.5-inch hard drives, with data pins on the left and power pins on the right. The two different pin lengths ensure a specific mating order; the longer lengths are ground pins and make contact first. (The cable side has similar variations to achieve three levels of mating order.)
File:SATA3-TwinAxCable.jpg|SATA cable showing the two foil shielded differential pairs
</gallery>

{{Clear}}