script to manually switch SPDIF red light on/off

Discussion in 'Mac Programming' started by basilt, Sep 5, 2016.

  1. basilt macrumors regular


    Aug 15, 2016

    I was wondering if anyone can help me with a script to turn on/off my SPDIF ports on the mac manually please.

    One of my ports is not glowing red and wondering if soundflower which is now removed or any other software switched the red light off.

  2. chown33 macrumors 604

    Aug 9, 2009
    So many bees
    Which Mac model? Exactly which port? Please be specific.

    If the port is TOSLINK only, then only output ports have a red LED. TOSLINK inputs have no LED, AFAIK.

    If the port is a combo headphone/TOSLINK port, then it will only have a red LED when a mini-TOSLINK plug is inserted. Again, only output ports (headphone) have a light. If the red LED is on when nothing is inserted in the port, then the plug-sensing mechanism inside the jack is defective (could be lint). Input ports (line in/mic in) have no LED.
  3. basilt thread starter macrumors regular


    Aug 15, 2016
    hello chown33 ! first of all thanks for the reply and secondly thanks for giving me the right word to look at on the web... Toslink. The ports state optical audio.

    my model is macpro DC 2.66Ghz xeon 1.1 with 2.1 update. 2006. i send screenshots also. please if you need further info let me know.

    From the photos i see on web, looks like a toslink port, but dont know why they call it S/PDIF on the other hand unless i get confused due to the lack of technical knowledge with audio stuff.

    I attach screenshot to see the ports also (pic no6). They are the square ones covered with a plastic cap/ door.

    On my macpro the right port marked OUT (as you see in photo) is glowing red when the maschine starts up.
    The other one is not lit at all for a reason, and i think that this might be the reason i have some sound problems.

    This is the reason i look for the script to see if it is disabled by software shich i dont have, as my mac is bought used a couple of days ago.

    Thanks again for your time replying to me :D

    Attached Files:

  4. chown33, Sep 6, 2016
    Last edited: Sep 6, 2016

    chown33 macrumors 604

    Aug 9, 2009
    So many bees
    An S/PDIF port can be either coax wire with RCA connectors, or TOSLINK. Only one of these is optical.

    The port marked OUT is an output. It glows red because the red LED is the transmitter.

    The port marked IN is an input. It won't glow at all, because it's an input, a receiver.

    To use the IN port, you plug in a TOSLINK cable, then plug the other end into an OUPUT port on another device.

    The OUTPUT port on that other device will be glowing red, because it's transmitting.

    As far as I know, IN ports will never glow red.

    You can't tell just by looking at the ports whether they're working. You'd have to connect the ports with TOSLINK cables to another TOSLINK device. If you don't have cables or a device, and can't borrow any, then you can't test the ports.

    No script can test the ports. You need to connect TOSLINK hardware and try it. If the ports work with TOSLINK cables and a device, then you can choose them as audio in and out. You won't need a script to do that.

    If you're having problems with sound, you need to describe exactly what the problem is.
  5. basilt thread starter macrumors regular


    Aug 15, 2016
    aha, ok ! At this point many things are more clear for me ! So, ports look ok, i just need to find toslink device to test them.

    Coming to the audio problem, i have the following issue.

    The audio i hear from the front speaker when it is i.e. 4 dots before max output, appears distorted, rattling.
    When someone speaks on Ytube, i hear his voice ok, but sometimes user pronouncing vowels and speaker
    distorts sound a lot, and sounds like sudden pops in voice.

    When i volume down all are fine, but then cannot hear sound well.

    Volume control keys working ok, on white keyboard, before a crash occured by reading a friends pc-formatted usb flash drive. After that my mac started responding very slowly when i was moving i.e. system preferences window or other
    windows GUIs on my screen. Programms were running ok though.

    I noticed a soundflower option in my audio prefs and decided to uninstall it and this caused further instability to my osx Lion.

    After i fixed this (i will re-format it soon though) my sound still has same problem as above
    PLUS the volume buttons on keyboard are disabled. No sound at all. I have to Alt-click sound menu and select
    internal speakers to activate it again. Then buttons work BUT NO clicking sounds when i volume up/down.

    I tried everything (PRAM, smc, terminal commands, plugging headphones etc) and buttons and audio problem does not correct at all. Further to this, sometimes when i hear audio from i.e. youtube, i volume up/down ok and suddenly Sound is Lost. Volume buttons works ok but no sound at all from speaker. I pause, replay video, no sound until i open a new video, then sound plays ok !

    Not sure now if i have to change backplane board or speakers or front board.... and apple diagnostics dont run on my lion.

Share This Page