DM-xxCC Default Display Values


Michael has really improved the look of his web site at The home page now features a carrousel of all five calculator models.

Mindlessly spinning the calculators, I started wondering why he chose the various default display values for each model:

DM-10CC = 1.7321
Easy, 3 SQRT

DM-11CC = 1.4142
Again easy, 2 SQRT

DM-12CC = 1.55
The best I that I can come up with is: 111 LN LN

DM-15CC = 1.6180
Pure gold, 5 SQRT 1 + 2 /

DM-16CC = AA55 H
Again, no idea:
BIN 1010101 Enter Enter 1001 RLn + HEX
HEX 55 Enter Enter 9 RLn +

Does anyone have a better solution for the DM-12CC or DM-16CC? Maybe Michael could give us the real answers.

Mark Hardman


About the "AA55": don't think too much about mathematics there, remember it's a programmers' calculator. And "AA" and "55" are two bytes often used for memory testing, as they have a peculiar bit pattern - AA is 10101010 and 55 is 01010101. So it might just be a tribute to old-style computer programming, which is what the 16C was for.


It goes back even further than that. In the old Teletype days (Western Union Telex et al), they used to send a line of "RYRYRYRYRYRYRY"... in order to "exercise" the send and receive contacts. These machines use the old 5-level (5-bit) "Baudot" code. R and Y are the TTY equivalent of 0xAA55 for memory tests --- their bit patters are 01010 and 10101 (but I don't remember offhand which is which).

They especially look nice punched into paper tape!

|  o   o   o   o   o   o   o   o  o

| o o o o o o o o

| o o o o o o o o o

| o o o o o o o o

| o o o o o o o o o

Dale, W8ABZ

(Don't ask how many Teletype (R) Model 19ASR, 28ASR and 32ASR machines I fixed back in the radio club in college days....)


I wonder what the keys of the ones with titanium housing will be like!

Possibly Related Threads…
Thread Author Replies Views Last Post
  [HP Prime] Constants Library Values Timothy Roche 24 7,248 11-02-2013, 04:17 PM
Last Post: Les Koller
  HP 35s - multiple program input values? Arno 3 1,622 04-29-2013, 11:27 AM
Last Post: Gerson W. Barbosa
  DM-1x Silver vs. DM-1xCC Aluminum quality? bhtooefr 11 3,286 04-14-2013, 07:08 PM
Last Post: bhtooefr
  [wp34s] Alternative MIO (allows calculations when entering element values) David Maier 1 1,040 02-03-2013, 02:51 PM
Last Post: Marcus von Cube, Germany
  Flashing the DM-15CC Geoff Quickfall 11 3,394 01-14-2013, 05:18 AM
Last Post: Mike (Stgt)
  Review of the DM-16CC hpnut 1 1,123 01-04-2013, 04:21 PM
Last Post: Guido (Canada)
  Default angle mode Eric Smith 71 13,687 12-06-2012, 01:19 AM
Last Post: Eddie W. Shore
  DM 15CC silver edition arrived! Hans Holzach 10 3,185 12-05-2012, 01:40 AM
Last Post: Juergen Keller
  dm-15cc battery life David Griffith 7 2,338 12-04-2012, 10:07 PM
Last Post: Walter B
  Can the display for a HP32Sii be replaced with the display from another model? Bruce Larrabee 8 2,809 10-10-2012, 10:05 PM
Last Post: Luiz C. Vieira (Brazil)

Forum Jump: