App note from Vishay about the dual terminator resistor network and how to check its internal resistor values. Link here (PDF)
One of the least understood resistor network schematics in the industry today is the dual-resistor terminator schematic shown in the 8-pin SIP and in the 16-pin DIP configuration.
This schematic shows up in both commercial / industrial parts and in military parts. Commercial parts are sometimes identified as TTL dual-line terminators or as pulse-squaring terminators.