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1 Digital 101 – I/O Connectivity Specs 5-2-99


[ VAIO | Linking | S/PDIF | Format Translator | Electrical | TOSLink | Coax | TTL | Details | Resources ]

Enabling Technologies – A Connected Digital Progression Unleashed! 
Update: See End Of Article – June 7, 2001
  1. PC Computer Audio Technologies

  2. WavToMidi Conversions

  3. Translator - Pro Sampler Audio Conversions

  4. SMDI – SCSI Musical Data Interchange


All of this technology yet how do we make the connections work for us instead of against us?

How do we keep digital in the digital domain without converting back and forth in analog formats through AD/DA converters? The Computer Audio/Video scene exemplifies new digital opportunities into ‘Desktop Digital Media Creation.’ Everything boils down to the end result – What’s our preferred method of transport & delivery now and later including MiniDisc, MP3, MP4, FireWire (IEEE 1394 – i.Link) 400 Mbps; S/PDIF (electrical & optical [TOSLinkTM mini]), etc.

Trying to connect your CD-ROM S/PDIF (Sony Philips Digital InterFace) connector to your sound card or MiniDisc Deck? Having trouble understanding S/PDIF digital I/O connections on SoundBlaster Live! audio cards and CD-ROM’s? The S/PDIF connector exists on most CD-ROM drives. Not all CD Drives activate this connection. Even fewer drive manufacturers mention S/PDIF use.

Just want to have fun preserving those old 33’s, 45’s or classic 78 LP’s onto your very own CD? Too much scratchy noise you say? Easy to fix! All of this and more can be done on today’s PC’s. In this article, we’ll highlight digital S/PDIF I/O connectivity issues and technologies. The relevancy pertains to sound cards, CD-ROM’s and MiniDisc S/PDIF (electrical & optical [TOSLinkTM]) connections.


Sony VAIO Digital Studio –

The “Digital 101 I/O” title derives from Sony’s 2nd stab into this web of digital fabric we now weave. VAIO is a graphical interpretation of the convergence of the analog and digital worlds (sine wave to the binary 101010). VAIO (pronounced "vie-oh"), stands for Video Audio Integrated Operation and represents the concept behind Sony's multimedia computer products. Sony’s goal of lifestyle integration is represented by the VAIO concept.

Even though we do not recommend a ‘ready built’ PC Computer box, Sony’s VAIO has most everything you want in one box except room for future expansion.

The Gotcha’s:
Limited Hardware Expandability - (1) available PCI Slot and (1) available 3˝-inch concealed drive bay.

The Hardware Pluses:
1.) FireWire (IEEE-1394) a.k.a. Sony I.LinkTM (S400) – Video / Audio (In/Out) Link.
2.) TOSLink a.k.a. LightPipe (developed by Toshiba), S/PDIF-optical audio link (AC-3 Dolby Digital Audio Out) and
3.) S.LinkTM (Control-A1 technology) – The Control Link interface, so far, exclusive to Sony.

Sony has taken their VAIO PC from a top of the line PII-450, 128 Megs of Ram, 13 Gig HD and DVD-ROM Drive to a PIII-500 with CD-RW. You may still be able to purchase the PII-450 from either the Online Sony Factory Outlet or Sony Factory Outlet Store in San Marcos, Texas (512) 396-1882. If you want VAIO, get a refurbished or customers return merchandise, with same ‘like new’ purchase warranties for a better deal. To see VAIO, go to MicroCenter where they may have the older PII-400’s available. Sony dropped the PII-450’s upon introduction of the newer PIII-500’s. These PIII’s are too expensive considering what you get for now.


Linking Technologies –

Although IEEE 1394 is an  "open standard," the i.LINK™ Sony name and logo brand the digital interface for high-speed communication on Sony products. Computers, peripherals, audio and digital camera products with i.LINK ports can be hooked together with a single cable for both data transmission/reception and control. Eventually we’ll see new motherboard chipsets, which have built-in native support of these high-speed technologies. IEEE 1394 / FireWire cables are still pricey and hard to find. See: www.monstercable.com

S-Link™ (Control A1) Control system was designed to simplify the operation of audio systems composed of separate Sony components. Control A1 connections provide a path for the transmission of control signals, which enable automatic operation and control features usually associated with integrated systems. For example, Control A1 connections between a Sony MiniDisc deck, CD changer, and VAIO Digital Studio Computer provide automatic function selection and synchronized recording. S-Link™ (Control A1) cables are usually included with Sony products which support this feature.

Sony has incorporated another advancement in the digital world with the Optical Digital Audio Output (TOSLink). This technology transmits digital audio data from a CD changer to MiniDisc via light impulses (Optical I/O) instead of conventional electronic signal, allowing for a clearer, crisper audio recording. TOSLink / Optical I/O cables are moderately priced depending upon manufacturer. Currently, MiniDisc TOSLink (Optical I/O) is for single digital copies. SCMS does NOT allow multiple digital copies.


The Sony Philips (Audio) Digital InterFace – S/PDIF Electrical Or S/PDIF Optical?

Not all S/PDIF connections wearing the same moniker are the same pin compatible, electrically compatible connection even though they share the same generic name. Yes they can be made to connect with a little help.

What’s the difference and why does it matter? Ever try connecting a Sound Blaster Live (Electrical) S/PDIF to an (Optical / TOSLink) S/PDIF MiniDisc Deck / Portable? For the purest, digital is digital and the preferred medium of choice. Once information is brought into the digital realm such said information is clean without distortion and reproducible as such. Or think of digital as no loss in quality over time or copy. An analog signal will eventually degrade beyond recovery and thus be lost forever. For example those old analog LP 78’s and 33’s are going to one day be history. Why not preserve their content by converting old LP’s to digital format thus archiving what otherwise might be lost. Using a PC for this makes easy use of digital technology – A different article.

Once in the digital domain, what if your analog and or digital creations happen to require yet a different choice of media delivery? This is why we’re discussing linking technologies. Media changes might require going beyond converting RedBook audio to wave or MP3 formats or moving from CD-ROM to PC to portable MP3 Player or MiniDisc or even DAT and of course Computer Hard Drives. We do have freedom of choice. Yet for now, we have to overcome some of the connection hassles in the process. Notice also the polarized organizational alliances of companies involved. Notice the linking technologies to get us where we want to go with Audio, Video and Data.


Digital (Audio) Format Translator –

Unless you’re handy with a soldering iron, Core Sound offers the ‘Digital Format Translator’ (DFT) to make your digital connections interface properly from MiniDisc to Sound Card. Both devices are digital, yet different formats with different connection requirements. The ‘Digital Format Translator’ product costs $95, plus $6 for the optional power supply. They also offer Fiber Optic Cables (TOSLink / mini - TOSLink and Mini-plug). The RCA (S/PDIF) cables are standard 75-Ohm video cables. MiniDisc recorders are also equipped with SCMS (Serial Copy Management System) which limits the number of possible digital copies that can be made (it is not audible and does not affect analog copying). In other words, this enables a stream to be marked as an original or a copy. A DAT recorder sold for the consumer market or digital recording studio component should mark as a copy anything it records from the digital input. DAT’s are not supposed to allow the user to make copies of material, which is already marked as a copy.  Many contemporary Pro DAT recorders though may be switched between consumer and professional mode. Pro mode overcomes SCMS. Does SCMS (Serial Copy Management System) hamper our creativity? See: www.ria.org vs. www.hrrc.org


Two types of electrical S/PDIF –

One type is commonly referred to as "Coax S/PDIF." The signal is typically carried along a 75ohm coaxial (RCA Video) cable. The signal voltage is +/-500mV. The other type is TTL S/PDIF (Transistor-Transistor Logic). TTL means the electrical signal is a 5V digital signal. Fiber-optic S/PDIF is called TOSLink. Less expensive MiniDisc recorders have only TOSLink digital inputs and outputs. If you wish to record MP3, WAV, or MIDI from a soundcard, you will need to convert the electrical S/PDIF output of the soundcard to TOSLink fiber optic of the MiniDisc.


TOShiba LINK (TOSLink) Digital –

TOSLink Digital standard was invented by Toshiba, and is widely used on all Sony digital audio equipment. TOSLink transmits the S/PDIF digital audio through fiber optics. The interconnect cables for TOSLink consist of glass or plastic fiber optic cables that transmit a 660nm red light from the source device to the recorder's input. There are two types of TOSLink! A.) Home Audio TOSLink connectors are larger .25" square. B.) Portable Audio mini-TOSLink connectors resemble 1/8" mini-plug (headphone-type) connectors. Most portable CD or MiniDisc players have multifunction jacks which act as both analog and digital input (or output) jacks. When an analog plug is inserted, the MiniDisc recorder auto-detects an analog connection and switches on the analog circuitry. When a digital fiber-optic mini-TOSLink cable is plugged into the same jack, the MiniDisc recorder auto-detects a digital cable connection.


Coax Digital standard

Many companies utilize the Coax Digital I/O standard. The connectors for coax are RCA (phono, or Cinch) type jacks. The S/PDIF digital data is carried electrically on a coaxial cable (a cable with an active center conductor and an outer-grounded shield). Coaxial cable is the same as regular 75-ohm RCA or phono cable. Coax's electrical standards are +/-500mVp-p (milliVolts peak-to-peak). This means the digital ZEROES are represented as -500mV while the digital ONES are represented as +500mV.


TTL S/PDIF standard

TTL stands for Transistor-Transistor Logic. TTL S/PDIF is most commonly found on computer CD-ROM drives that are equipped with a digital audio output. Some inexpensive PC soundcards also have a TTL S/PDIF input and output. The connector type used is most commonly a 2-pin header. It is similar to Coax in that the S/PDIF data is transmitted electrically, however, where it differs is in its voltage levels. TTL digital ZEROES are represented as 0V, while TTL digital ONES are represented as +5V.


For S/PDIF (Sony/Philips Digital Interface) Details:

If you don’t understand S/PDIF, read it again! Easy to see why most companies do NOT define S/PDIF standards to the public through documentation. The easiest way to understand S/PDIF – Just look! Must be that Missouri blood in me! (Missouri, the “Show Me” State.) Digital IS the future and the future is NOW! Distribution is the key. Next Up – MiniDisc, Internet Audio: MP3 & MP4 and Streaming Technologies. It all gets easier! ;)


Moving Forward – June 7, 2001 Update

This article, originally written for print, though dry and l-o-n-g was very timely considering the Digital Desktop Recording Studio Access Revolution, which started full force in 1998. No longer were we relegated to consumer game 16 bit sound cards. We now were getting into affordable access to 24 bit / 96 KHz pro audio / prosumer / working musician worthy audio cards differentiated by better specs, better drivers, better gear and better prices from professional level manufacturers who made Desktop Audio affordable by using PC Computers as our Recording Studios.

As technology grows, we have new acronyms and terms, greater flexibility through better interoperability – Yamaha’s mLAN (1394 - FireWire), ALESIS 20-bit ADAT optical (lightpipe) ports, etc. to name a few. We hope by making this information available, we’ve helped you in making sense of making it all work together! People And Technology Working In Concert! It’s all about new ways of invigorating those creative juices @ odd hours when the moment is right and the genius flows.

Now CD-ROM’s with S/PDIF are mostly irrelevant since we rip CD’s as wav files to the HD. Even playback in real time is preferably done digitally. Apps such as Microsoft’s Windows Media Player 7 play back CD (RedBook) Audio digitally, not as analog through the little audio cable but digitally through the data cable. This alleviates other problems with more CD drives in a PC than a Sound Card has connections for them. A hardware problem solved by smarter software.



In time, we will update this resource document with further research. If you have a particular interest or correction, please let us know.  

Gill Boyd, Former HAL-PC VP Programs
BuildOrBuy Group Network News -
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Web Development, Gill Boyd & Team - Created 5-2-99, Posted & Updated 06-09-2001; Revised 01/07/2006