M20 Olivetti M20

Andreas Senk M20 collection

Andreas has several very nice M20s and a very interesting piece of hardware.

Three M20 The family: three working M20s: from left to right there is a D, a DES and a ST.

M20DES An Olivetti M20 DES with a mysterious piece of hardware, from Olivetti.

M20DESA particular of this peculiar DES version.

The Mistery BoxThe mysterious box attached to the M20 DES. The black thing on the front is a keyhole. Maybe a protection system? Or an hardware watchdog system?

External label of the boxThe back label of the external box

The controllerThe controller inside the M20, connected to the external box.

The controllerThe controller. The big chip on the center of the board is a programmable interrupt generator.

Another view of the controllerAnother view of the internal controller.

Inside Mistery BoxThe inside of the external box: see below!

M20 DES motherboardThe M20 DES motherboard

Mystery box solved!

The Mistery Box Andreas Pittini sent us some interesting information about this strange piece of hardware: this is (was!?) a special feature for a tax accountant. The "Mystery Box" on your homepage i know as special DATEV-Device. This is for turning on the PC at night for receiving data from remote.

20 years ago they was simply collecting data and transferred them to DATEV. (DATEV had a big computing centre for doing the calculations and storing the data for years).
The transfer of the data could be done at night, so DATEV simply called the M20 by phone.
btw: tax accountants always have had a M20 DES! (see also the PCOS "sl"-Command and option 16 (DATEV))

Andreas Senk, the owner of the M20 DES added: The NEC D8253 mounted to the expansion card a timer chip. If I switch off the M20 at the normal mains switch, only monitor, drives and some parts of the board loses power. The rest is powered from internal power supply in the box. So it might be that an incoming call is recognized by the additional card and box and powers the M20 up to full status. The timer chip then seems to activate the sleep mode after a given time again.

DATEV eG is a German association for tax consultants, auditors and lawyers.

Thanks Andreas!

Page log

  • December 23, 2022 - Included info about DATEV (originally in the front page of the website.
  • April 27, 2007 - Page updated
  • June 30, 2006 - First version of the page

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