At my work we have a bunch of old computer and logic stuff. I figured it would be best to ask about it here, since the original owners have long since retired. Any ideas what this thing is and what it was for?
Caveat: ATM I can not identify the machine this was taken from. I can only describe what can be said from parts visible. I will not go into further speculation.
Seems to be part of a front panel (i.e. blinkenlights) to some machine. Hard to say anything more detailed.
It's most likely a 12 bit system, as switches and lamps are organized as four groups of 3 each, which is typical for octal handling.
It can't be said if this is from a 'real' Computer, some IO processor or 'just' some controller, without further information.
Still, the 'POWER CONNECTORS' and 'I/O CONNECTORS' lamps seem to indicate that it's from some communication and/or I/O orientated system.
The 'POWER CONNECTORS' seem to be static assigned to (maybe) show activity on either line
The 'I/O CONNECTORS' (may) show activity on either line/device
The switches are most likely to set an address, which can be a memory address, some I/O register or channel address.
It is only intended for reading/checking data, as there is only a single set of switches and no visible controls to latch address and/or data (*1)
Operation is most likely (*1) done by
- setting an address with the switches
- switch position gets reflected on the lower row of lamps
- any data at that address will be shown on the top row
Together ('I/O CONNECTORS' and 'data' lamps in single row) this might provide a nice display of actual activity. Quite useful to check if a certain functionality is operating the way it should (*2).
The 'LAMP CHECK' button does exactly that, ignite all lamps to see check for defects - quite common at a time when lamps weren't LED like today.
*1 - Unless there are not additional controls outside the picture, in another, missing panel.
*2 - Imagine the address being a status word of a serial interface, thus showing activity on either line, or conditions why there is no activity. Looking why a certain (modem) line is not operational (or why the remote user claims so) was one of the most common tasks.
A "switch register" or "sense switches" provides a way for the CPU to read a binary input without explicitly using the I/O bus. Due to the name "switch register," I would expect these switches to be mapped directly to a register accessible to the CPU. For a made-up example, if the CPU had 8 registers, one of them (let's say, register 0) would be mapped to the front-panel switches. Writes to that register would do nothing; reads from it would reflect the position of those switches.
A switch register was especially useful for interacting with bootstrap programs, for selecting the input device or other options, or for controlling diagnostic programs, but of course any program capable of reading that register could make use of them.
I'm not familiar with this particular model but this type of "front panel" was found in many early mainframe, mini, and micro computer systems. While this example is among the simpler ones, and may be from a micro computer system, these all worked similarly.
They were used to program the system word by word and were often used to input a "boot loader" that would load the operating system from some other device like a paper tape reader or a disk drive.
These work by setting the memory address on the switches and then seeing the memory content at that address and then depositing a value set by the switches into that memory location. Often they had an "auto-increment" that would automatically increment the address to the next some so that you didn't have to manually enter the next address.
Overall it was quite tedious using these which is why they have pretty much disappeared except in some retro models out there.