[Discuss] OT: what is this cable for?

[j.natowitz at rcn.com (Jerry Natowitz)]

Chipcom  had a series of telco ethernet modules that were part of the ONline hub product line.  They supported either 12 or 24 ports, and some modules supported fault-tolerant switchover.

Here is a description of during the 3Com years, when ONline was renamed "CoreBuilder 5000"

The CoreBuilder 5000 Ethernet 24-Port Module is an IEEE 802.3
repeater module that complies with the 10BASE-T standard. It connects
up to 24 devices (PCs, terminals, printers, modems, etc.) to the
CoreBuilder 5000 hub. Two 50-pin Telco-type connectors connect to
24 10BASE-T-compliant ports using 25-pair 10BASE-T cables or 12-leg
"hydra" cables.

---- Original message ----
>Date: Wed, 2 Nov 2011 11:23:03 -0400
>From: discuss-bounces+j.natowitz=rcn.com at blu.org (on behalf of "Ricker, William" <William.Ricker at FMR.COM>)
>Subject: Re: [Discuss] OT: what is this cable for?  
>To: Dan Kressin <dkressin at yahoo.com>,BLU Discuss <discuss at blu.org>
>
>>? Ribbon cable w/ two (the name escapes me ..) "ring things" to usually used to fight inductance..?
>
>Snap-on Ferrite donuts actually *add* inductance, which rounds the corners of square wave digital signals, to prevent interference (both by and to) and/or induced spikes from lightning EMP. They come in a variety of specs which attenuate into progressively lower frequencies. Use the wrong one and you'll attenuate the desired signal too ! 
>
>(One more pedantic than I might object that fighting interference is fighting *mutual* inductance, but that's not a measurable inductance outside of cross-talk range.)
>
>Yes the DA-15 was used as Game/MIDI port on early IBM PC ISA sound cards. But the normal MIDI adapter cable would have been DA-15 to pair DIN-5 (or XLR3). Since the game port was re-used to drive all sorts of things, that's a possible origin, as are any custom frobistats. The C-50 / CN-50 was abused as an easy expansion interface for lots of pre-miniaturization devices -- it was originally a family or range of telco analog connectors for twisted pair snakes, eg multi-line phones & PBX to punchblock cabling, that was adopted for printers, re-adopted for SCSI-1, because it was available relatively cheap due to volume of telco use. As the RJ series has been adopted more recently. The C-36 had obscure computer uses, not sure if larger sizes were ever digitally 'appropriated'.
>
>Bill @ $DayJob
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