ID unmarked Mini DIN-4 cables (ADB vs S-Video or ?) pins etc

[1moremac]

Hi,

I'm trying to ID some unmarked Mini DIN-4 cables (ADB vs S-Video vs ??) from a mixed parts box - and don't have an Apple brand cable to compare with.

Using a cheap old continuity tester, looks like two types (for both pins seem wired straight through)

1) The cylindrical shells on each end are connected through the cable

2) The cylindrical shells on each end are isolated from one another

Also found a couple of web references which say either ADB and not S-Video - OR - S-Video and not ADB - connect the shell with the ground pin - which I didn't find for any of the cables.

Thanks.

 

[techknight]

ive used s-video cables as ADB cables in a pinch, they worked fine.

 

[1moremac]

ive used s-video cables as ADB cables in a pinch, they worked fine.

Thanks. Getting the impression the differences may only matter to a select few peripherals on the Mac side.

 

[tmtomh]

Yeah, I was always under the impression you could use them interchangeably. And I've never had a problem doing so.

I also was under the impression that the shielding was the difference, which probably explains the different readings you're getting on the shells.

Easy way to tell would be if you had a genuine Apple ADB cable - say, a coiled keyboard cable. Do the continuity test on the shells, and you'll have your answer.

 

[Trash80toHP_Mini]

They are interchangeable, but S-Video cables make very good ADB Cables and ADB Cables make very poor S-Video Cables.

The shell on any cable is invariably grounded, it's not connected to the ground lines at the signal level because it's connected to the RFI shielding of the Computer. The signal level lines are for clean ground level connections and the Logic boards are connected to the RFI shielding at specific points that are designed into the PCBs where RFI won't be problematic.

The requirements for RFI shielding for ADB signals are paltry as compared to video signals, there are huge differences in the frequencies involved to be shielded from the environment for FCC approvals and for signal integrity within the cable. ADB is duck soup, S-Video ain't.

The above is my understanding of the situation, BTW, not a statement of fact.

 

[LCGuy]

I've been using S-Video and ADB cables interchanagably for years, never had a problem doing either.

 

[coius]

I have had a varying quality of ADB cables, but over time as they get bent/twisted it seems to degrade as it either breaks the RF shielding strands in the cable causing interference, or sometimes it can degrade the connections of the wires to the pins. Now-a-days, ADB cables suck for S-Video due to the age plus the low standards of how they are made. ADB doesn't pass as much data, and at the same rate/constant that S-Video does, so it really doesn't need to be built to the quality of S-Video.

However, S-Video was partially designed to replace component cables as it uses the RGB + sync signal (or ground) which can cause a poor quality than Component but it does much better than composite (with a smaller connector)

S-Video will obviously give you a better signal than composite, but at a slightly increased cost due to splitting the signals, the timing and the requirement for stricter cable quality construction. ADB cables from Apple (and maybe NeXT which I believe also uses it) don't need to meet the quality as Texas Instruments and Apple (I think both had a hand in designing it) both decided they only needed a certain quality to keep the price down and since it doesn't matter too much on the data transfer (and I think had error correction on it too with encoding).

S-Video carries analog vs digital of the ADB, so S-Video can't correct signal like ADB does.

Either way, the pins are the same on both ends between ADB and S- video. The only real difference is the data they carry and the strict quality they have to meet.

ADB cables work as S-Video in a pinch, but I wouldn't use them to do a presentation on an old projector. It will not make a good presentation with a fuzzy pie chart.