bsexton, The 6552 is source series terminated so you do not require any additional termination. You may, however, place additional differential parallel termination at your MC100ELT23 receiver of 100ohms and drive two channels of the 6552 with complementary data. Keep in mind, though, that this will result in a voltage divider. If you are powering the MC100ELT23 with a 5V supply (Table 4 specs of the data sheet at http://www.onsemi.com/pub_link/Collateral/MC100ELT23-D.PDF) then the 6552 will need to provide a VHIGH of > 3.84 and a VLOW < 3.52 at the pins of the receiver. If you don't add additional termination then you can achieve this by setting VOH > 3.84 and VOL to < 3.52 with the recommendation of keeping the common mode (VOH + VOL / 2) between 2.2V and 5V. With the additional termination, your swing will be cut in half so in order to have the same 3.52 to 3.84 swing, your VOH would need to be 4V and VOL would need to be 3.36V.Hope that helps.