IEEE 1394, Thunderbolt & SATA Connections

Some of the slightly less common, but no less important connection types

IEE 1394
The Institute of Electrical and Electronic Engineers (IEEE) 1394 connection is a high speed interface for peripheal devices that are designed to use the IEEE 1394 Standard.  Products that use this standard include Apple’s FireWire, Texas Instruments Lynx and the Sony Corporations iLink.

The IEEE 1394 supports plug-and-play devices and hot-plugging of up to 63 devices on one port.  IEEE 1394 is also able to power devices and is most often used to connect devices such as camcorders, external hard drives and digital cameras.

A 4 conductor (left) and 6 conductor (right) alpha firewire 400 connector

Similar to USB, there are multiple versions of the IEEE 1394 Standard, all of which transmitting data in a digital, rather than analogue, format:

  • The original IEEE 1394, also known as FireWire 400, was first released in 1995 and specified a 6-conductor alpha connector.
    • Distance Limitation:  Maximum cable length 4.5 Metres
    • Transfer Speed: 400 Mbps
    • Signal Quality: Uses isochronous data transfer to assist in reducing buffering of multimedia applications or video/audio streams.
    • Frequency: 33Mhz
  • IEEE 1394a was released in 2000 and introduced the 4-conductor alpha connector, as well as boasting other additional feature enhancements.
  • IEEE 1394b, also known as FireWire 800, was released in 2002 and has a 9-pin beta connector.  This made the FireWire 800 incompatible with legacy cables, although this was overcome with the availability of bilingual cables.
    • Distance Limitations: Maximum cable length: 100 Metres
    • Transfer Speed: 800 Mbps
    • Signal Quality: As with IEEE 1394, uses isochronous data transfer to assist in reducing buffering of multimedia applications or video/audio streams.
    • Frequency: 25 MHz
Thunderbolt Connections

Thunderbolt connections are high-speed I/O interface that consists of a host controller that can join together PCI-Express data or DisplayPort video.  After being combined, the signal is sent through a full-duplex pair or differential signals and this supports the connectivity of a wide range of peripheral devices, up to 6 at a time, including external graphics displays, storage devices, audio devices and even full 4K video displays.

A Thunderbolt Connector
Cabling for Thunderbolt connections is available in both copper wire and optical fiber.  Again, data transmitted through Thunderbolt connections is done so in a digital format.
    • Distance limitations:  Maximum cable length for copper wire is 3 Metres and for optical fibre is 60 Metres.
    • Data Transfer Speeds:  Version 1: 10 Gbps per channel (20 Gbps total).  Version 2: 20 Gbps per channel (40 Gbps total) and Version 3: 40 Gbps per channel (80 Gbps total).
    • Signal Quality:  Thunderbolt devices, as with IEEE 1394 connections, transfer isochronously (steady stream) which makes both audio and video very precise in real time.
    • Frequency: 430 kHz fixed switching frequency.
SATA Connections
In one of my earlier posts, I took a brief look at HDDs, including SATA HDDs.  As with all drives, there has to be an interface between that and the computer unit itself, in order for communication to take place.  A SATA connection provides a serial data channel between teh drive controller and the disk drives themselves.  SATA transfer speeds are much higher than that of their legacy connections of same drive technologies.  SATA connections have seven pins and have the additional bonus of being easier to physically install due to their smaller, thinner and more flexible cables.

SATA (left) and eSATA (right) connectors

As the name implies, External SATA connections (also known as eSATA) are an external interface for SATA connections.  Similar to USB and IEE1394 connections, eSATA provides a connection for external storage devices. One additional benefit of eSATA over USB and IEE1394 is that it’s able to provide fast data transfer speeds without having to translate data between the connected device and the host computer.  However, eSATA devices do require an additional power connector in order to function.  eSATA connectivity is provided through the installation of an eSATA expansion card into a computer unit.

eSATA Ports

All SATA connections are of a digital nature.

    • Distance limitations: 1 Metre
    • Data Transfer Speeds:  SATA I; 1.5 Gb/s. SATA II: 3.0 Gb/s.  SATA III: 6.0 Gb/s.  SATA 3.2: 16.0 Gb/s.  eSATA: 3.0 Gb/s
    • Interface Throughputs: SATA 1: 150 Mbps.  SATA II: 300 Mbps  SATA III: 600 Mbps  SATA 3.2: 1969 Mbps.  eSATA: 30 mbps
    • Frequencies:  SATA I: 37.5 MHz.  SATA II: 75 MHz.  SATA III: 150 MHZ

It’s worth noting that SATA II is backwards compatible with SATA I and that SATA III is backwards compatible with both SATA II and SATA I.

Study Reference Disclaimer.

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