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Palmtop PC's - Skolob's Hewlett Packard 95LX Palmtop

skolob | 14 March, 2007 10:06

The little compact HP 95LX released in 1991 weighed in at a tiny 11 ounces, the device also only occupied the space of two chequebooks glued back to back (6.3 in x 3.4 in x 1 in) and could run on on two AA batteries for up a month! This made it one excellent portable device and MS-DOS computer for use on the run, today it is highly collectable!

I have written up my own modern day FAQ with information I have gained on this device over the years. Ive compiled information on on serial port pin outs, hidden features, battery saving tips, important keys, avoiding the dreaded hinge crack, infrared transfer information and much more.

Also included is hidden easter egg information for the 95LX, 100LX and 200LX devices.

Skolob's Hewlett Packard 95LX Palmtop Page

Photo of my HP 95LX

Copyright (c) 2005 - 2007 SKOLOB.CO.UK by Vauxhall.
May not be reproduced or copied without permission.
Revision : 14/Mar/2007

The 95LX has a 8086-compatible MS-DOS computer with either 512k or 1Meg of memory.  

History of the HP 95LX computer
The history of the HP 95LX handheld computer is available from HP at :


Production Dates
The device was introduced on the 23th April 1991 for US$699 until 1st January 2003. There was an estimated production run of about 400,000 devices.


Keystroke Commands
Useful keystroke commands in the 95lx available anywhere in the system :

[CTRL]+[ALT]+[DELETE] - Reset Device
[CTRL]+[SHIFT]+[ON] - Initialise RAM Disk
[SHIFT]-[SETUP] - System Setup (only available from menu)


How do I access MS-DOS?
Select [Filer] from menu, then [Menu] Key and then press [S]. The system will now be in full MS-DOS mode, the version of DOS. To return to Filer type in EXIT at the DOS prompt then press [Enter] key.

All the usual DOS commands can be used - heres a small sample :

DIR - List files
DIR /P - List files a page at a time.
VER - Display current DOS version


Reducing battery consumption
It is a known fact that the 95lx can effectively keep the serial port 'open' even if it is not in use. This can slightly increase the drain on the batteries. To prevent this drain goto DOS and type in :


See topic below for turning serial port back on for when its needed!


Full syntax of the SERCTL command
SERCTL is a command in DOS that allows turning on/off of serial/infrared services.

SERCTL /O Turns off the power to the active port.
SERCTL /W Turn serial port on
SERCTL /I Turns infrared port on.


Full syntax of the DISPCTL command
DISPCTL is a command in DOS that allows turning on/off cursor tracking/alt arrow key movement.

Due to small size of 95lx screen not all screen data can usually be viewed at once. Cursor tracking attempts to automatically adjust the screen to show the 'active' part. It can be a problem with some programmes, therefore it can be turned off and on using the DISPCTL command. The DISPCTL command can also enable or disable the ATL-Arrowkey screen movement command on or off.

DISPCTL +C Cursor tracking on
DISPCTL -C Cursor tracking off
DISPCTL +K ALT+Arrowkey screen movement on
DISPCTL -K ALT+Arrowkey screen movement of

System Self Test
There is a built in system self test system for testing display, RAM, ROM, Plugin Card, Timers, Infrared, Serial port and Keyboard. To access the Self Test menu, insure the device is off then press [ESC]+[ON], then a menu will appear! WARNING! Plugin card test may destory any data on cards plugged in!


Avoiding the common HP palmtop hinge crack!
Although hinge cracks are far more common on later 200lx models due to the tightness of the hinge you should always treat the 95lx with care. Shut the device from the right hand side because this is where the hinge mechanism is. When shutting from the right, ensure you are not just holding the top edges of the device while shutting as this puts the maximum pressure on the hinge. The lower down and closer to the hinge you use your hands to shut the device the better.

How do I know if I have the dreaded hinge crack?
With the device shut, sitting in front of you. Look in the right edge corner of the case, for any lines near the join of the top panel with the rounded hinge! It may look like a scratch, but it is more than likely to be a hairline hinge crack. If you have this crack, open and shut the device carefully - as otherwise eventually the hinge will completely snap.

Serial Cable pinouts for 95LX
The serial cable pin outs for the HP48 calculator which according to a number of references on the internet is the same as the 95lx pinouts. (I cannot 100% confirm this fact, so please use these details at your own risk.)

HP48 | RS232-9 | RS232-25
1 | shield | shield
2 | 2 | 3
3 | 3 | 2
4 | 5 | 7


Transfering files to HP 95LX using Infrared using a iPAQ Pocket PC
One method of transfering files to and from the device is via the Infrared beam. The Infrared beam uses the HP SIR protocol and is generally incompatible with most Windows 98/XP infrared devices. A simple simple alternative I found was using an old iPAQ Pocket PC and using a HPSIR compatible file transfer programme to send the data across. 


Games for the 95LX : Hidden TigerFox Game
A game called TigerFox is included on the 95lx, (may not be available on all versions!), it can be accessed by entering the command TF in DOS. 


Games for the 95LX : Tetlix Tetris Clone Game


  Level 0 / 1     █▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒█
  Score   158     █▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒█
                  █▒▒▒▒▒▒▒▒▒▒▒▒  ▒▒▒▒▒▒█
                  █▒▒▒▒▒▒▒▒      ▒▒▒▒▒▒█
     TETLIX       █▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒█
  Right = -->     █▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒█
  Left  = <--     █▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒█
  Drop  =  ↓      █▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒█
  Rotate= F1      █▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒█
  Pause = F2      █▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒█
                  █▒▒▒▒▒▒▒▒   ▒▒▒▒▒▒▒▒▒█
                  █▒▒▒▒▒      ▒▒▒  ▒▒▒▒█
                  █                ▒▒▒▒█

A tetris clone for fans of this type of puzzle games. This can be downloaded from our web server here.

Hidden Easter Eggs within the 95LX and other models 
With the palmtop off, hold down [Esc] and press [On]. The palmtop enters its ROM-based self-test mode. (Warning! Do NOT run the Plug-in Card test on a flash card - it will destroy data! This test is meant for older SRAM cards only!)
Cursor down to the Display test, then...
For HP 95LX, 100LX and 200LX:
Press [Enter] 14 times to step through the display modes, and you will see a limerick about a caveman.
For 100LX and 200LX:
Press [Ctrl]+[Enter], then hold down [Alt] while pressing [Enter] 13 times. You will see a cryptic poem, presumably about troubles the HP developers went through.
For 200LX: 
Press [Ctrl]+[Enter], then hold down [Shift] while pressing [Enter] 13 times. You will see a poem about Jaguar, Cougar and Felix (the codenames for the 95LX, 100LX and 200LX).
Assembley Image for HP 95LX
 HP 95LX Assembly Image




jones | 01/05/2007, 20:21

many thanks

This 95LX rocks!

Jack | 15/09/2007, 11:52

This is a brillant PDA device that I used to own, I also have an 200LX although its suffering with the hinge crack. Please could you ad more 95LX software to this page?

Hewlett Packard MS-DOS PDA 95LX

Joseph | 15/09/2007, 11:53

The Hewlett Packard HP95lX rocks! Still the best PDA today!

Dont forget you can do programming on the HP95LX via DEBUG.COM

Paul Smith | 17/09/2007, 15:20

If you go into the hidden directory "_SYS" youll find a copy of DEBUG.COM where you can write programmes using intel's assembly language! Here is an example I found : C>debug -a 1E0A:0100 mov bx,1 1E0A:0103 mov cx,f 1E0A:0106 mov dx,110 1E0A:0109 mov ax,4000 1E0A:010C int 21 1E0A:010E int 20 1E0A:0110 -e 110 1E0A:0110 00.48 00.65 00.6c 00.6c 00.6f 00.2c 00.20 00.57 1E0A:0118 00.6f 00.72 00.6c 00.64 00.21 00.0d 00.0a -r cx CX 0000 :1f -r bx BX 0000 :0 -n -w Writing 001F bytes -q C>hello Hello, World! C>


Paul Smith | 17/09/2007, 15:25

Useful tip for 95LX! Exponentiation can be done on the CALCULATOR in HP95LX. An example is, to calculate the fourth root of 16 in algebraic mode type: 16 ^ (1/4) and press .

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