Jaap's Psion II Page

Psion Organiser II Models and Version Numbers

There are several different models of Psion Organiser II, and even more versions of the operating system in its ROM. This page will tell you how to find out which model and version you have.

Consumer Models

The first Series II models came out in 1986, and had a 2-line display. The model CM had an 8K RAM, and the model XP 16K. The XP was almost immediately upgraded to 32K Ram, and although the casing was still labelled as XP, it is often referred to as the model LA. All these models had a 32K ROM.

Most of the Organisers produced were English, i.e. the menus and error messages were all in the English language. Other single language versions were made too, in particular French and German versions. Eventually a multi-lingual XP model was made that had a choice of 11 languages. Its ROM was extended by two 16K banks to 64K to store this extra data.

In 1989 Psion started producing models with a 4-line display. The model LZ had 32K Ram, and the LZ64 had 64K (32K plus two 16K Ram banks). It looks virtually the same as the older models, except that the screen is slightly taller. They were all multi-lingual, with a choice of English and two other languages, usually French and German. The Scandinavian model had English, Swedish, and Danish language choices.

Finding Out The Model

To know which model you have, you can select the CALCulator option in the main menu and type:


When you press EXE it will display a number that is different for most base models.

The following table shows most possibilities:

PEEKB(-24)Model ROMRAMDisplay
0 CM 32K8K 2x16
1 XP 32K16K2x16
2 XP(LA) 32K32K2x16
2 Multilingual XP(LA)64K32K2x16
14 LZ 64K32K4x20
13 LZ64 64K64K4x20


To check the language options, you can enter PEEKB(-25) in the calculator.

0 or 255 English only (CM/XP/LA)
1 French only (CM/XP/LA)
2 German only (CM/XP/LA)
128 11 languages (Multilingual LA)
129 3 languages; English, French, German (LZ/LZ64)
130 3 languages; English, Swedish, Danish (LZ/LZ64)

ROM version

The version of the operating system in the ROM can be discovered by evaluating PEEKB(-23). This is a binary-coded-decimal number, so if it contains the hexadecimal number $46 for example then the ROM has version number 4.6 etc. Here is a table with the version numbers with most common ones shown in bold type:

362.4 (CM/XP*)
372.5 (CM*/XP*)
382.6 (CM/XP)
483.0 (CM*/LA)
493.1 (CM*/LA*)
503.2 (CM*/LA*)
513.3 (CM/LA)
523.4 (CM*/LA*)
533.5 (CM*/LA*)
543.6 (CM/LA)
553.7 (Multilingual LA)
563.8 (POS350)
664.2 (LZ/LZ64*)
674.3 (LZ*/LZ64)
684.4 (LZ/LZ64)
694.5 (LZ/LZ64)
704.6 (LZ/LZ64)

If you have any of the versions marked with an asterisk, a version in an non-English language or one not listed here, I would like to have a copy of its ROM contents to add to the ROM Image page.
You can contact me at .

POS Models

There are several variants produced for use in industry and retail. These variants are normally called POS (Point-Of-Sale) models. When switched on, a POS model does not supply a menu, but instead looks on the packs for a procedure named BOOT and runs it. If no such procedure is found, it displays "PACK?" or "INSERT PACK?" for a moment and then switches off. These models often have unusual keyboards.

There are POS variants of the LZ/LZ64 models too. I don't know if these were produced with non-standard keyboards.

129POS 200 32K16K2x16Numeric
130POS 200 32K32K2x16Numeric
65 Alpha POS 20032K16K2x16Alpha-numeric
66 Alpha POS 20032K32K2x16Alpha-numeric
17 P 250 32K16K2x16Full
18 P 250 32K32K2x16Full
20 P 350 32K96K2x16Full
30 P 432 64K32K4x20Full
29 P 464 64K64K4x20Full

Devices and Packs

Many devices such as the Comms Link have internal software that is loaded into the Organiser. Such software has a version number that can be read out. Connect the device, switch the organiser on, and in the main menu press ON/CLEAR to make sure the software is loaded. In the calculator, evaluate PEEKB(8441).

Certain software packs also have version numbers. Insert the pack, switch the organiser on, and in the main menu press ON/CLEAR to make sure the software is loaded. In the calculator, evaluate PEEKB(8421) for slot B: or PEEKB(8431) for slot C:. Note however that only bootable packs have a version number, and that many software packs use the standard boot loader version 1.0 that Psion supplied with the Organiser Developer package. On packs without a version number the peek will give a meaningless number.

PEEKB Version
0 0.0
1 0.1
2 0.2
3 0.3
4 0.4
5 0.5
6 0.6
7 0.7
8 0.8
9 0.9
16 1.0
17 1.1
18 1.2
19 1.3
20 1.4
21 1.5
22 1.6
23 1.7
24 1.8
25 1.9
32 2.0
33 2.1
34 2.2
35 2.3
36 2.4
37 2.5
38 2.6
39 2.7
40 2.8
41 2.9
48 3.0
49 3.1
50 3.2
51 3.3
52 3.4
53 3.5
54 3.6
55 3.7
56 3.8
57 3.9
64 4.0
65 4.1
66 4.2
67 4.3
68 4.4
69 4.5
70 4.6
71 4.7
72 4.8
73 4.9
80 5.0
81 5.1
82 5.2
83 5.3
84 5.4
85 5.5
86 5.6
87 5.7
88 5.8
89 5.9