IMP11-A ARPANET interface
From Computer History Wiki
The IMP11-A ARPANET interface is a UNIBUS network interface produced by DEC's Computer Special System division to connect allow a machine to connect to an ARPANET IMP.
It consists of a BA11-E Mounting Box holding a pair of DR11-B parallel interfaces (one for packet input, and one for output), and a custom backplane holding a number of M-series FLIP CHIPs.