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Tektronix 1225
48 channel logic analyzer
Tektronix 1225

Produced from 1988 to 1993

Manuals – Specifications – Links – Pictures

The Tektronix 1225 is a logic analyzer introduced in 1988 that supports 16 to 48 channels, 100 MHz asynchronous, 25 MHz synchronous.

The 1225 is equivalent to the Tektronix 1220 but has one more 16-bit probe input. It is also very similar to the Tektronix 1230 on the outside, but on the inside the layout is different − the 1225 has three probe inputs instead of four and the boards are stacked horizontally instead of vertically.

The 1225 was one of Tektronix' efforts to make an "easy to use" logic analyzer aimed at students and engineers. The user interface clearly represents that mindset. The menus are simple and there are help guides everywhere guiding the user in what he might want to do.

The 1225 did not have the same expansion capability that the 1230 had. The only expansion available were the option boards, of which four were available − parallel printer interface, RS-232 interface, GPIB interface, and on-line notes in foreign languages. Tektronix also had a software package (S43R101) that would run on IBM PC compatible machines.


Number of channels 48 channels
Probes either P6444 or P6443 (16-channel)
CRT 13 cm × 10 cm
Power 90-250 V
Weight 8.6 kg (19 lb.)
  • Composite output
  • RS-232 (optional)
  • Printer port


The 1225 is built around a 65C02 as the control processor with 104K of SRAM, and 128K of firmware in a bank of EPROMs. There is a separate board under it that manages the display and keypad, which is powered by another 65C02 CPU and is using an MC68A45 CRT controller to drive the display. The display board has 56K of RAM and 8K of ROM, with two coin cell batteries to retain settings. There is a bug that prevents the 1225 from keeping the date after the year 2000. Upon powering it off and on again it will revert to 19xx, e.g. 2018 will turn into 1918.

Easter egg

An "Easter egg" can be activated in the 1225 by pressing the STOP button when the welcome screen shows during power-up. A bar with the programmers' names will display near the bottom of the screen.