This is a Programmable Logic Controller (PLC) made by Arcom Controls (now EuroTech), a vendor of SCADA (Supervisory, Control And Data Aquisition) equipment, mainly for the oil and gas industries. 
Arcom's president, Arlen Nipper and IBM's Andy Stanford-Clark collaborated on the development of the MQTT messaging protocol in 1998. MQTT is now an ISO/IEC standard (20922), and is the predominant messaging protocol for the Internet of Things (IoT). This device was the first commercially available product to implement the MQTT client software, and was used to publish data from sensors connected to it to a remote MQTT broker: WebSphere Message Broker. The device could also subscribe to commands which it would pass on to actuators such as relays, pumps and valve controllers. Several thousand of these devices are still operating in production environments for large oil and gas companies in the USA. 

I think the one in the museum is the one with lots of signatures on, isn't it? 
We all signed it at the MQTT 10th Birthday Party (in 2009). 

(To mark the event of MQTT’s 10th birthday, we had a bit of a party for those that have been involved over the years. Arlen Nipper and Andy Stanford-Clark, the fathers of MQTT were there to tell the tale of how it all came to be.)

See pictures here: http://mqtt.org/2009/07/10th-birthday-party 

It is true that my MQTT mousetrap also used one of those Arcom FieldSentry devices, though. I know the actual device for that is in my garage, though :)