Can you identify this 14-pin DIP resistor network?
As Jonta says what you have there is a TTL Dual-Line Terminator / Pulse Squaring resistor network.  An example datasheet is here.  The internal circuitry is shown in the figure below:



Specifically you have a 330/470 Ohm version like the on here.

You have commented that you are reading between 60 and 70 ohms between the ground and common lines (pin 7 and 14).  This is correct!  If you study the schematic above, the equivalent resistance between those two pins would be twelve (330+470) Ohm resistors in parallel, or about 66 Ohms.

As the datasheet linked above states, these resistor networks are used for TTL dual-line termination and pulse squaring.