This terminal has been made by Ericsson in early 1980s
for Swedish Datasaab E2500. Datasaab E2500 is mainframe system for
business and banks, made since early 1980s. According to "Tema
D21" (Ventzel V. et al, 1994,), in 1983 a D16 mainframe architecture
has been redesigned to E2100 for business and E2500 for bank
The life of these mainframes was not significantly long as for bank applications - it was in 1980s, PCs became more popular, yet introduction of Ericsson's PCs went not as good as they expected. Some of them survived for some time in bank sector, where if the system works it is more profitable to keep it running (2019: there is still COBOL and some branch of dBase used in banking software), but they became replaced by better Unix solutions. Terminals have been connected to concentrators using coaxial cable, like in IBM 3270 line, or using twinaxial pair for larger distances (like IBM 5250) and probably offered similar, if not larger, capabilities including forms building, simple data processing for the mainframe and loading of templates. This terminal has some unusual characteristics. First of all, it is a really high-end as for 1980s. There is a plenty of RAM - 128kB, and it is powered with Motorola 68000 CPU. Yes, 68000, like early Macs or Amiga. The HD68450 DMA controller is used to maintain memory and devices accessible. Display is generated with AM8052 controller. We also have a dedicated DRAM controller and serial port chip which is converted to coaxial or dual-wire connection and keyboard port. Many PCs of that era were slower than this terminal.
An unusual thing here is its branding: Inside, it has components from 1981..1983. In front, it's Ericsson (then there were connections of Ericsson with Datasaab). On the rear we also have two more brands: Alfaskop which made Swedish terminals for along time since at least 1970s and also has Ericsson connections, and, surprisingly, Nokia Data. Nokia Data acquired Alfaskop much, much later, Ericsson/Alfaskop/Nokia Data devices became seen around 1987..1988. This is quite strange and device could be serviced for a longer time after acquisition, when the sticker was applied.
|Manufacturer:||Ericsson / Datasaab|
|Display:||External monochrome (?) CRT|
|Main port:||Coaxial or Twinaxial|
|Additional ports:||Expansion connector,
Connectivity expansion connector
Peripherals in collection:
|In my unit, the board has been corrected in many places and
numerous times using enameled copper wires. It looks like thee
were some tracks made wrong and corrected and some obvious ones
just not exist (then added with this wire), so it may be an
early revision of board. The board is quite complex, 4-layer
one. The socket for CPU is not stable and CPU may pop out is
device is rotated too much. EPROMs are also in unstable sockets,
secured by small drops of solder.
There are also some unusual interfaces used. It looks like the display signals are sent not directly as signals, but using 4 current loops. Additinally with the same connector we have two power voltages and some unnknown signal (maybe sound or video which could not be crammed into current loop?). The keyboard is connected with an own serial port which also carries power for it.
WARNING: My unit is highly modified so it may vary. Also really untested.
1, 4, 5, 6, 7 - GND
2 - Output from computer (??clock??)
3 - I/O from/to computer (??data??)
8,9 - 5V, fused.
Display - unknown current-loop connector:
1, 2, 14, 15 - Voltage A
4, 17 - Voltage B
5, 10, 12, 13, 16, 18, 23, 25 - N.C.
6, 19 - Output 1
7, 20 - Output 2
8, 21 - Output 3
9, 22 - Output 4
11 - GND
24 - Output???
Voltage A and B are probably monitor power. There is an unregulated few tens of volts between these two leads, about 80V, don't know it is OK or not.
Power supply unit:
X X X X X X X X X X X . X . X
15 ... ... 1
1 - Voltage A
2, 4 - NC
2 - Voltage B
5,7,9,11,13 - GND
6,8,10,12 - +5V
14, 15 - ?NC? (not conncted to PSU)
http://www.datasaab.se/Bildarkiv/S2500/Miljo/miljo_eng.htm - Datasaab E2500 description