Lost Mac Plus keyboard cord

[Gorgonops]

How do we know it's not static electricity? I think we need more people to try this and see what happens.

Or maybe that's a really foolish and terrible idea?

According to the pinout if you use a rolled telephone cord in place of Apple's cord you'll be putting +5v to ground on the keyboard end, which is plenty to destroy integrated circuitry of that era. The fact that it didn't happen to you could be, as mentioned before, "luck", or I suppose it's possible, depending on the vintage of your keyboard, Apple might have started fitting the ground line with a protective diode just in case to cover users if they made this mistake. (That's utter speculation based on nothing, I don't plan on cracking open the two RJ-11 keyboards I have to see if there might be a difference like that between the early keypad-less one and the plus keyboard.) Seriously, don't just "try it" unless burning up old computers is your idea of a good time.

 

[Dog Cow]

That's utter speculation based on nothing, I don't plan on cracking open the two RJ-11 keyboards I have to see if there might be a difference like that between the early keypad-less one and the plus keyboard.) Seriously, don't just "try it" unless burning up old computers is your idea of a good time.

Dan Kottke, digital engineer at Apple who co-designed the Macintosh keyboard with Ed Riddles, says otherwise:

"[COLOR=rgb(15.7%,16.1%,15.7%)]The ke[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]y[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]b[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]oar[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]d [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]connects [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]th[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]M[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]ac[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]in[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]tosh [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]v[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]i[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]a [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]a [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]m[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]od[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]ular [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]co[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]il [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]cord [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ha[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t i[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s s[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]i[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]m[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]il[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]a[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]r [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]o [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]thos[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]u[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]sed o[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]n t[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]l[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ep[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]hon[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]es. [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]The [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]Mac[/COLOR][COLOR=rgb(42%,43.1%,42.8%)]'[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s co[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]rd h[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]as [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]h[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]eav[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]i[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]er [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]ga[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]u[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ge w[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]ir[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]to [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]prevent [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]drop[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]in [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]vo[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]lt[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]age [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]that don[/COLOR][COLOR=rgb(42%,43.1%,42.8%)]'[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]t [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]t[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]p [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]yo[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]u [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]f[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]r[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]m [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]und[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]e[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]r[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]a[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]ndin[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]g [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]ph[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]n[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]e co[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]nv[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ersa[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]ti[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]n[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]s [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]but [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]can int[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]er[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]fer[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]with the accur[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]ac[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]y of [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]th[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]e [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]digi[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]a[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]l [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]s[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]i[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]g[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]n[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]a[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]l[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]the [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]Ma[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]c [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]u[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ses. [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]If[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]yo[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]u [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]r[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ep[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]l[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ace [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]the [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]Mac[/COLOR][COLOR=rgb(42%,43.1%,42.8%)]'[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]c[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]rd [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]w[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]ith [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]a [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]t[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]l[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ep[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]h[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]n[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]h[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]andse[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]co[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]rd[/COLOR][COLOR=rgb(34.5%,36.5%,35.7%)], [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]it [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]doesn't damage the keyb[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]oa[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]rd[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]'s [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]m[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]i[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]cro[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]proce[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]sso[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]r[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)], [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]but it [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]wo[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]n't [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]work. [/COLOR]"

Source: MacWorld Sep-Oct 1984, pg 35.

 

[Juror22]

I'm sure Dan had collected a large quantity of experimental evidence on the Mac 128, Mac 512 and Mac Plus and all their associated keyboards and revisions by August of 1984, but you will excuse me if I don't accept this as authoritative, despite the source.

Given the variables involved and scads of evidence that others have lost hardware over this, I will not be plugging phone cords into my vintage Macs.

 

[tomlee59]

Dan Kottke, digital engineer at Apple who co-designed the Macintosh keyboard with Ed Riddles, says otherwise:

"[COLOR=rgb(15.7%,16.1%,15.7%)]The ke[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]y[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]b[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]oar[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]d [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]connects [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]th[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]M[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]ac[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]in[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]tosh [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]v[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]i[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]a [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]a [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]m[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]od[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]ular [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]co[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]il [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]cord [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ha[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t i[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s s[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]i[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]m[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]il[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]a[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]r [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]o [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]thos[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]u[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]sed o[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]n t[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]l[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ep[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]hon[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]es. [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]The [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]Mac[/COLOR][COLOR=rgb(42%,43.1%,42.8%)]'[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s co[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]rd h[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]as [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]h[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]eav[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]i[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]er [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]ga[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]u[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ge w[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]ir[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]to [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]prevent [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]drop[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]in [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]vo[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]lt[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]age [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]that don[/COLOR][COLOR=rgb(42%,43.1%,42.8%)]'[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]t [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]t[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]p [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]yo[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]u [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]f[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]r[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]m [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]und[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]e[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]r[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]a[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]ndin[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]g [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]ph[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]n[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]e co[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]nv[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ersa[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]ti[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]n[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]s [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]but [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]can int[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]er[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]fer[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]with the accur[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]ac[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]y of [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]th[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]e [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]digi[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]a[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]l [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]s[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]i[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]g[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]n[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]a[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]l[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]the [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]Ma[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]c [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]u[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ses. [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]If[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]yo[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]u [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]r[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ep[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]l[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ace [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]the [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]Mac[/COLOR][COLOR=rgb(42%,43.1%,42.8%)]'[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]s [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]c[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]rd [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]w[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]ith [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]a [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]t[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]l[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]ep[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]h[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]o[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]n[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]e [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]h[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]andse[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]t [/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]co[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]rd[/COLOR][COLOR=rgb(34.5%,36.5%,35.7%)], [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]it [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]doesn't damage the keyb[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]oa[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]rd[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]'s [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]m[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]i[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]cro[/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]proce[/COLOR][COLOR=rgb(27.1%,28.2%,27.1%)]sso[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]r[/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)], [/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]but it [/COLOR][COLOR=rgb(21.2%,22.3%,21.2%)]wo[/COLOR][COLOR=rgb(9.8%,9.8%,9.4%)]n't [/COLOR][COLOR=rgb(15.7%,16.1%,15.7%)]work. [/COLOR]"

Source: MacWorld Sep-Oct 1984, pg 35.

Note that Dan is a digital engineer. He has clearly not run many (or any) experiments, and is just voicing an opinion. He would not get a good grade in my circuits classes. His answer about the "heavier gauge wire" is utter nonsense. The currents flowing (both signal and power) are so small that any voltage drops would be completely negligible. The real reason for the incompatible cable is simply that Apple has traditionally wanted to force users to buy Apple widgets.

In contrast with Dan, I'm an expert in the sense that I have learned from the vast number of mistakes I have made, or have seen others make, whence wisdom and scar tissue derives.

When you use an ordinary telephone cable in place of the correct keyboard cable you are applying power to the keyboard in REVERSE POLARITY. You are not simply "grounding 5V". Although doing so doesn't guarantee keyboard destruction, it certainly makes it likely. You are relying on the Mac's power supply limiting the current to a value below that which would destroy the keyboard electronics. That's an unsafe bet, as the current limit is set to protect the power supply, not devices connected to it.

As to your static electricity hypothesis, note that the impedance levels are much reduced on the keyboard when reverse polarized. If static electricity were strong enough to destroy the keyboard in that condition, then you would see a great many failures from static electricity when using normal cables.

It ain't static. It's reverse polarity. No more experiments needed, and no appeals to Kottke's ill-founded opinions will change that.

 

[Gorgonops]

When you use an ordinary telephone cable in place of the correct keyboard cable you are applying power to the keyboard in REVERSE POLARITY. You are not simply "grounding 5V".

To be clear, that's what I said, if not quite so clearly; you're applying +5v to the side of the circuitry in the keyboard that's supposed to be connected to ground.

(Obviously the real "ground" in the circuit is on the Mac side, not the keyboard. And, yes, by flipping the leads you've connected the "positive" side of the keyboard to that. So yes, if current flows it's going to be in reverse.)

Seriously, there's no defense for suggesting people try this for laughs *and* that quote from the Apple "engineer" is just gobbledygook. Telephone cables work if you cut the end off and flip the pinout, Dog Cow said that himself, for sheesh's sake! 

 

[unity]

Note that Dan is a digital engineer. He has clearly not run many (or any) experiments, and is just voicing an opinion. He would not get a good grade in my circuits classes. His answer about the "heavier gauge wire" is utter nonsense. The currents flowing (both signal and power) are so small that any voltage drops would be completely negligible. The real reason for the incompatible cable is simply that Apple has traditionally wanted to force users to buy Apple widgets.

In contrast with Dan, I'm an expert in the sense that I have learned from the vast number of mistakes I have made, or have seen others make, whence wisdom and scar tissue derives.

When you use an ordinary telephone cable in place of the correct keyboard cable you are applying power to the keyboard in REVERSE POLARITY. You are not simply "grounding 5V". Although doing so doesn't guarantee keyboard destruction, it certainly makes it likely. You are relying on the Mac's power supply limiting the current to a value below that which would destroy the keyboard electronics. That's an unsafe bet, as the current limit is set to protect the power supply, not devices connected to it.

As to your static electricity hypothesis, note that the impedance levels are much reduced on the keyboard when reverse polarized. If static electricity were strong enough to destroy the keyboard in that condition, then you would see a great many failures from static electricity when using normal cables.

It ain't static. It's reverse polarity. No more experiments needed, and no appeals to Kottke's ill-founded opinions will change that.

I take it you dont know who Dan is....

 

[tomlee59]

Seriously, there's no defense for suggesting people try this for laughs *and* that quote from the Apple "engineer" is just gobbledygook. Telephone cables work if you cut the end off and flip the pinout, Dog Cow said that himself, for sheesh's sake! 

Yes, exactly. It's so easy to do it right that there isn't any justification for trying the wrong way just to see what happens. Applying power backwards to semiconductors rarely results in a happy outcome...

 

[unity]

*and* that quote from the Apple "engineer" is just gobbledygook.

I am more surprised you dont know who his is.

 

[Gorgonops]

I am more surprised you dont know who his is.

I had to remind myself, and... am I supposed to be impressed? Apparently he was a music major in college that got his job at Apple because Steve Jobs liked doing LSD with him. He may well have learned enough ad-hoc electronic knowledge in the trenches to put together various digital tinkertoys, but there's a lot of room there to suspect that his word shouldn't be considered even remotely like gospel on a matter like this. Not to mention the fact that he may well just have been talking out of his *** when he was quoted in that magazine article because he didn't actually *remember* why it was a bad idea to use a telephone cord for the keyboard. He may well have had nothing to do with the final decision of how the connectors were laid out.

 

[unity]

Well he helped design the original Macintosh keyboard. So there is that.

Dont get me wrong, I am not saying he is right or wrong. I dont have the schematics handy to actually look. But is was more than just an LSD using buddy of Jobs, he did a lot of board level work. So I would not dismiss him so easily.

 

[Gorgonops]

I'm not saying he didn't have any talent, but nonetheless his job title at Apple for a *long* time was "technician", not "engineer". He did take some extension courses and managed to convince Apple to upgrade his job title so he could say this:

"On the Macintosh, I was the one who did the keyboard, which was a single-chip computer, a computer subsystem. That was my first embedded system project."

But... really, this discussion isn't about how good of an engineer Dan was or was not, it's whether that statement makes any sense, and clearly it doesn't. Applying reverse voltage to TTL/CMOS electronics is a demonstrably bad thing, and the keyboard pinout of the Mac isn't a mystery, that is what you're doing when you use a telephone handset cable in place of the Apple one. I have personally destroyed electronic devices by plugging universal power supplies set to the incorrect polarity into them, so unless they *specifically* included protection against that eventuality in the keyboard it is indeed nothing but luck that would let you survive doing it.

I will throw this out there, just for laughs: I kind of wonder if Dog Cow might have plugged in a *2* conductor RJ-11 cable instead of a 4 conductor cable when his mac survived it. If you only connected the center two pins reversed then, sure, that probably wouldn't hurt anything since you'd only be crossing the data and clock wires while leaving the keyboard unpowered. I just checked the POTS telephone on my desk and, yes, its handset cord has only 2 conductors. Quite a few phones do.

 

[unity]

You might be right about the two pin. If I recall, most headsets only used two wires anyway. They did not the the ringer wire.

edit: nevermind, that would not make sense. Still need at least a third for ground.

 

[Gorgonops]

The phone I looked at was one with the dial in the handset. My guess is that the base has essentially nothing in it and is just passing tip and ring from the wall through it, thus only needing two wires.

 

[Dog Cow]

 I will not be plugging phone cords into my vintage Macs.

You'll have no argument from me on that point, as there's no practical reason to use an unmodified handset cord!

 

[Trash80toHP_Mini]

I take it you dont know who Dan is....

He likely does, but it doesn't matter a bit if he didn't. I take it you don't know who tomlee might be? You can take anything he says to the bank. Search terms like Stanford, Electrical Engineering, ScD MIT etc.

It's great to see you around these parts again comrade, professor lee! You've been much missed.

 

[Dog Cow]

I will throw this out there, just for laughs: I kind of wonder if Dog Cow might have plugged in a *2* conductor RJ-11 cable instead of a 4 conductor cable when his mac survived it. If you only connected the center two pins reversed then, sure, that probably wouldn't hurt anything since you'd only be crossing the data and clock wires while leaving the keyboard unpowered.

No. That evening, I used a 4-wire RJ-11 handset cable. I tested it with the telephone and heard the dial tone. Then I took it to the Mac 512K, connected it, and typed on the keyboard with the Mac powered on. No results. Replaced it with the official Apple coil cord and everything worked.

Then I cut that first RJ-11 handset cable, reversed the conductors, soldered together, tested it on the telephone. Didn't work. Tested it with the Mac 512K. Worked. Now it's a second Mac keyboard cable because I was missing one.

That's what happened.

 

[Gorgonops]

Congratulations?

There is nothing about this that proves that using a telephone cable isn't at best useless and at worst very dangerous, nor does it do anything to support the quoted gobbledygook that the reason a phone cord doesn't work is the "quality of the wires". (In fact it manifestly disproves it.)

(There also remains the possibility that some keyboards may be equipped with a diode or current limiting resistor to protect the keyboard in the event of this mistake while others lack it. Or your keyboard might just have mutant superpowers?)

 

[re4mat]

Retrofixes sells replacement cables for $10:

https://store.retrofixes.com/collections/retro-computer/products/new-macintosh-128k-512k-512ke-plus-compatible-keyboard-cable