Siemens MultiKom S1

This is another Bildschirmtext (BTX) terminal released in Germany for their network. BTX was a telephone-based network with information pages, telephone registry or some services such as bank information, ticket reservation or news. This terminal is quite late one, from 1990, with a Deutsche Bundespost logo (German Post Office), but it was made by Siemens as their modular design used in Multitel/Bitel models was getting older and more expensive. Some newer technologies have been used here, like EEPROM memory instead of battery-backed SRAM, logic arrays minimizing amount of 74-chips used or modem-in-a-chip circuit made by AMD. The power supply unit is built in monochrome, CRT-based monitor.
The unit is password-protected by default, after entering password it is possible to choose numbers from registry, configure unit or enter terminal mode using serial port. The external power for printer/modem is supplied by the unit, as well as we have serial and parallel ports for printer or external modem. The unit has 64kB of dynamic RAM and is based on MC6803 microcontroller with its own 128-byte RAM. The internal modem is based on AMD WorldChip FSK modem in a single IC.
According to some manuals, the keyboard is roughly AT-compatible. Looking at this PLA logic I haven't dared to try.
There were more models in MultiKom series, in early 1990s even a version of Loewe Multitel D (white one) was called Multikom L1. Of course it had an older, Loewe's modem design and battery-backed memory. I think that the main reason of so large diversity among these terminals was similar like one in beginings of French Minitel - standards were not strict enough. MultiKom Script was Multikom S1 with typing machine/teletype capabilities added.

A nice description of BTX service is in Multitel D page.

Manufacturer: Siemens

Model MultiKom S1
Year: 1990
CPU: Motorola 6803
Memory: 64kB of RAM
Display: CRT, monochrome, white
Keyboard: External
Main port: Telephone line
Additional ports: Centronics port for printer
V.24 serial port for modem
Serial port
Printer/monitor port




User manual

Starting manual

Peripherals in collection:
 - Original box, screen shield and manuals

 - Keyboard card for ASCII terminal

My unit is in a very good shape. It looks like it was unpacked, used shortly and then packed back to box. There is a handwritten note in the manual stating that the password is "kennwort" ("password" in German), and it indeed opens the system, with probably OEM phonebook full of BTX services. Contrary to earlier units this one has no cleartext password in ROM and I haven't analysed where it should be present. For my unit, I decided not to change password.

Controls, pinouts (source: Starting Manual)

Monitor/printer connector:

1 - Monitor blanking
2 - GND
3 - Printer ready
4 - Printer? / Monitor COmposite Sync
5 - Printer enable
6 - Printer? / Monitor Green
7 - Printer? / Monitor Blue
8 - Printer? / Monitor Red

No idea how exactly the printer is connecter nor how it operates.

Modem V.24, printer:

1 - DCD
2 - Rx
3 - Tx
4 - DTR
5 - GND
6 - DSR
7 - RtS
8 - CtS
9 - RI

PRINTER is 4800bps, 8bit, 1start, 1stop bit, Standard EPSON German.

Centronics port:

2 - D0
3 - D1
4 - D2
5 - D3
6 - D4
7 - D5
8 - D6
9 - D7
11 - BUSY
16 - INIT
18-25 - GND
10,13,14,17 - N.C.

Links: - In BTX Museum - Manuals for some BTX machines, standard descriptions