What exactly does the blue switch in the 3178 keyboards?

[PlacaFromHell]

Hello guys. I traded an IBM model F XT to Karl Martin for one of his 3178 keyboards. After a little talk we realized that there is no info about what this thing do. What is the original purpose of such a weird thing?

[sharktastica]

My guess is that it would have changed all the characters on the terminal's display to uppercase (hence the legends that make it seem like another caps lock).

[PlacaFromHell]

My guess is that it would have changed all the characters on the terminal's display to uppercase (hence the legends that make it seem like another caps lock).

I guessed something similar, but I have no way to confirm it.

[Chyros]

I've heard people say it does that too.

[yuchipashe]

Did a quick google search regarding the IBM 3178 and found this announcement letter from IBM:

https://www-01.ibm.com/common/ssi/ShowD ... _locale=en

which stated

Publications
GA18-2127 'IBM 3178 Display Station Description'
available now
GA18-2128 'IBM 3178 Display Station Operator Reference
Guide' available at first customer
shipment
GA18-2153 'Supplement to IBM Display Station Operator
Reference Guide' available at first
customer shipment

And a quick search of "GA18-2128" shows this large documentation of the "GA18-2081-1" documentation finds a whole documentation regarding the Display station keyboard and what each key does, specifically "IBM 3270 Information Display System: 3276 Control Unit Display Station Description and Programmer's Guide":

There are a lot if interesting info regarding the different functionalities of every keyboard, but I believe the answer to your question is this

https://archive.org/details/bitsavers_i ... 0/page/n43

Alphabetic characters on typewriter keyboards attached to 3276 displays can be entered
into the display buffer in either uppercase or lowercase code, depending upon the
position of the Shift key. However, only uppercase alphabetic codes can be entered
| from data entry keyboards. On 3178,3276,3278, and 3279 displays, alphabetic
characters in the buffer (uppercase or lowercase codes) are displayed as all uppercase
or uppercase and lowercase characters, as determined by the setting of the Dual Case/
Mono Case switch. The shift keys on the Katakana keyboards operate differently from
the keys described here; refer to Appendix E for details.

https://archive.org/details/bitsavers_i ... /page/n243

Dual/Mono Case Switch. When in the Mono Case (A) position, only uppercase characters
are displayed. When in the Dual Case (A,a) position, uppercase and lowercase characters
can be displayed. This switch is located on the right side of the CRT.

https://archive.org/details/bitsavers_i ... 0/page/n85

Mono/Dual Case Control


When power is applied, the 3287 is activated to print mono-case; other terminal printers
are automatically activated to print the dual-case character set.

In dual-case operation, the alphabetic character codes sent by the host determine
whether uppercase or lowercase characters are printed, provided that the print belt
has the dual-case character set. In mono-case operation, the lowercase alphabetic
character codes print equivalent uppercase characters.

The Change Case switch can be pressed to change the print case on the terminal printers.
However, when operating with LU1 printers in SNA, die data character codes and the
print belt character set determine whether mono- or dual-case characters are printed,
regardless of the Change Case switch setting.

In a BSC environment, when using the Copy command to transfer data from a display
to a printer, the setting of the Change Case switch on the “from” display determines
mono- or dual-case in the “to” printer. When the Copy command transfers data from a
display or a printer to a display, the Change Case switch on the “to” display determines
whether mono- or dual-case is displayed.

Controls of the 3276/3278 with the "Dual/Mono Case Switch":

https://archive.org/details/bitsavers_i ... /page/n241


Looking at the 3178, there is no button for "Dual/Mono Case Switch", with the only switch on the base system being the Power and TEST/NORMAL switch. Since there is no documentation online for the 3178 (so far, at least. Since every Displaywriter comes with this documentation, I bet it's sitting somewhere ready do be scanned to archive.org), I might be completely off and wrong though, but if anyone wants to go deeper into this rabbithole and read through IBM documentations regarding the systems and keyboard functionality, update me if you find something interesting

[yuchipashe]

My guess is that it would have changed all the characters on the terminal's display to uppercase (hence the legends that make it seem like another caps lock).

Dual/Mono Case Switch. When in the Mono Case (A) position, only uppercase characters
are displayed. When in the Dual Case (A,a) position, uppercase and lowercase characters
can be displayed. This switch is located on the right side of the CRT.

You're probably spot on with that

[Weezer]

I have the german operation manual, and set up instructions for the 3178 terminal and the keyboard, and I recall one of the two states something similar to the theory here.

[Weezer]

Yep here it is.


Achtung: Steht der Schalter auf Großschreibung (A), werden alle angezeigten Zeichen nur in Groẞschreibung angezeigt. Steht der Schalter auf Groß-/Kleinschreibung (A, a), werden die Zeichen in Groß-/Kleinschreibung angezeigt.

Attention: If the switch is in upper case (A), all displayed characters are only shown in upper case. If the switch is in upper / lower case (A, a), the characters are shown in upper and lower case.

Since the 3178 was a "low-cost" variant of the 3278, it seems likely the switch was kept for compatibility but was moved to the keyboard as part of the cost cutting process.

If there is a need or a desire to see the full pamphlets, let me know and I'll upload a full PDF. There are several pages describing the functions of nearly every key on the keyboards offered with the 3178.

[sharktastica]

That's some awesome information, yuchipashe and Weezer!

About the pamphlets. If you're willing, I would be interested in a scan of any of the keyboard sections for archival purposes. I'm also working on an exhaustive Model F/Model M family tree/website thingy, and that could provide some invaluable information. Completely up to you though since I'm actively looking for physical manuals anyway.

[PlacaFromHell]

Lol, that's a huge investigation work. Thanks guys! So, it's already impossible to mantain the original purpose of the blue switch in a converted keyboard, that's a bit sad but at least we know what is meant to.

[sharktastica]

Lol, that's a huge investigation work. Thanks guys! So, it's already impossible to mantain the original purpose of the blue switch in a converted keyboard, that's a bit sad but at least we know what is meant to.

In computer science, impossible is a term that's impossible to define! The switch is still a just switch, so theoretically you could wire it up to separate controller (Pro Micro, for the sake of cost) that could tell the host PC to do something. Using Windows as a proof of concept, you could write a simple C# 'server' that could be triggered to modify Windows' registry to change the default system font to a font that's all uppercase. I know that's hardly a portable solution (you'd have to install the server on every computer you intend to use the keyboard with) and probably not worth the hassle, but when I get my hands on a blue switch, it's not gonna stop me from trying it.

However, IMO, the more practical use of the switch would be to rewire it to toggle the solenoid. I think I recall others doing so in the past? Not sure how easy of a job that is since I'm yet to be familiar with Xwhatsit. But if it comes to it, you could just create an indepedent circuit for that I guess.

[PlacaFromHell]

Lol, that's a huge investigation work. Thanks guys! So, it's already impossible to mantain the original purpose of the blue switch in a converted keyboard, that's a bit sad but at least we know what is meant to.

In computer science, impossible is a term that's impossible to define! The switch is still a just switch, so theoretically you could wire it up to separate controller (Pro Micro, for the sake of cost) that could tell the host PC to do something. Using Windows as a proof of concept, you could write a simple C# 'server' that could be triggered to modify Windows' registry to change the default system font to a font that's all uppercase. I know that's hardly a portable solution (you'd have to install the server on every computer you intend to use the keyboard with) and probably not worth the hassle, but when I get my hands on a blue switch, it's not gonna stop me from trying it.

However, IMO, the more practical use of the switch would be to rewire it to toggle the solenoid. I think I recall others doing so in the past? Not sure how easy of a job that is since I'm yet to be familiar with Xwhatsit. But if it comes to it, you could just create an indepedent circuit for that I guess.

That would be awesome, but I have too many projects to start a new one, especially of so high complexity. They keyboard itself has a "solenoid lock" key but as in my 3101 I use it as an alt key. I want to use the keyboard as my portable field daily driver because of the layout, so I have to think calmly what could be more useful (that doesn't stop me to end up doing something as stupid as a shift lock, for example).