# What do the keys on this circa 1960 adding machine do? **URL:** \ **Category:** Factual Questions\ **Created:** [June 8, 2011, 3:12am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704 "2011-06-08T03:12:41Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [June 8, 2011, 3:12am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704/1 "2011-06-08T03:12:41Z")
The unit works perfectly, but I would prefer not to keep beating up the old, dried out ribbon with trial and error exercises. I understand everything except the keys to the far left. The"C" key, the “#” and the up and down slide with the X at the bottom. They do not seem to do anything obvious in running calculations if I press them randomly while adding strings of numbers. I could figure it out with trial and error, but I would prefer not to beat up the 50 year old ribbon. Anyone familiar with these old units? [Pic here](http://img694.imageshack.us/img694/8708/img3649dv.jpg) ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [June 8, 2011, 3:17am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704/2 "2011-06-08T03:17:57Z")
If it’s anything like my circa 2005 adding machine the C is Clear as in, reset/start over and the # as far as I’ve ever been able to tell (without reading the directions) just puts a number on the left side of the tape. I’ve always assumed it’s so you can look back at your tape and have some way to sort of make notes as you go. I’ve never found the # sign to actually interact with the arithmetic in any way. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [June 8, 2011, 3:21am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704/3 "2011-06-08T03:21:50Z")
> [@Joey\_P](#): > > If it’s anything like my circa 2005 adding machine the C is Clear as in, reset/start over and the # as far as I’ve ever been able to tell (without reading the directions) just puts a number on the left side of the tape. I’ve always assumed it’s so you can look back at your tape and have some way to sort of make notes as you go. I’ve never found the # sign to actually interact with the arithmetic in any way. Pressing the “C” after an entry does not clear any memory registers that I can see. The inputs are unaffected when totaling. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [June 8, 2011, 3:35am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704/4 "2011-06-08T03:35:07Z")
Joey P is correct about the # sign – it’s a way of entering numbers on the tape for reference, but they are not entered into any calculation. It’s been a while since I used one of those, but I thought the C key would clear the current, but not yet printed, entry. IIRC, you type the numbers sequentially, then press the plus or minus key to get them to print and be tabulated. Example: Type “123”…nothing prints…press “+” and “123” prints and is entered to the accumulator (there’s only one register). If you made a mistake before pressing the “+”, the “C” will clear that entire entry line before anything prints. Example: Type “12”, C, “34” “+” and “34” will print. Is that how it works? ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [June 8, 2011, 3:39am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704/5 "2011-06-08T03:39:25Z")
What’s the manufacturer name? ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [June 8, 2011, 3:46am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704/6 "2011-06-08T03:46:42Z")
> [@Boyo\_Jim](#): > > What’s the manufacturer name? Underwood 288. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [June 8, 2011, 4:12am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704/7 "2011-06-08T04:12:54Z")
A person who goes by the name [vaxomatic](http://www.classiccmp.org/pipermail/cctech/2009-September/108481.html) had a handful of these things in 2009. I suspect they kept at least one for themselves so they may be able to fill you in on the details of the “x” and S/T switches. As for the ribbon, you may be lucky and find that cheap generic calculator ribbons fit. Worst-case scenario would involve re-spooling a new ribbon onto the 288’s spools. ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [June 8, 2011, 10:45am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704/8 "2011-06-08T10:45:31Z")
S is subtotal and does not clear the total from memory. T is total clearing the memory. C should be clear. It’s probably clear the current numbers you have just punched but not entered by hitting the plus or minus sign on. The x switch down probably allows the number last punched to be retained and just hitting the add button will allow it to be added again without punching the number. I don’t have this model so I’m going on how others I’ve used have acted in the past. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [June 9, 2011, 12:36am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704/9 "2011-06-09T00:36:54Z")
Thanks for info! ---
**Author:** ![Siam\_Sam](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Siam\_Sam](https://boards.straightdope.com/u/Siam_Sam)\ **Post date:** [June 9, 2011, 1:49am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704/10 "2011-06-09T01:49:45Z")
Now that the question has been answered, I just want to say that I felt really, really old when I saw an adding machine as a museum display here. ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [June 9, 2011, 2:19am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704/11 "2011-06-09T02:19:01Z")
> [@Siam\_Sam](#): > > Now that the question has been answered, I just want to say that I felt really, really old when I saw an adding machine as a museum display here. I felt a lot older, as my reaction was, “That’s not an adding machine, that’s a calculator. Adding machines have handles to pull!” ---
**Author:** ![Michael\_of\_Lucan](https://avatars.discourse-cdn.com/v4/letter/m/dbc845/32.png) [@Michael\_of\_Lucan](https://boards.straightdope.com/u/Michael_of_Lucan)\ **Post date:** [June 9, 2011, 9:47am UTC](https://boards.straightdope.com/t/what-do-the-keys-on-this-circa-1960-adding-machine-do/584704/12 "2011-06-09T09:47:02Z")
Curiously, one of my former colleagues used a machine like this until he retired a couple of years ago. He also had a normal calculator which he used for most purposes. The advantage of using the old machine was that he got an immediate paper print-out of the calculation, which could be attached to documents he was working on. It showed the breakdown of the cheque which he was issuing.