What is a convenient method to both terminate the transmission line and attenuate the signal at a differential receiver input?
A convenient method to both terminate the transmission line and attenuate the signal at a differential receiver input is to employ a differential attenuating termination. All this means is that the termination at the end of the transmission line uses voltage division to attenuate the signal seen by the differential receiver.
For an example, please see the attached figure, Example_Differential_Attenuating_Termination.png. A nominal 100 Ohm differential termination has been implemented using 3 each 33 Ohm resistors. The termination seen by the transmission line is 99 Ohms differential, yet the the voltage signal to the receiver has been greatly attenuated, in this example, down to 1/3 of its value prior to the termination.