bob@uhmanoa.UUCP (Bob Cunningham) (09/18/87)
Parts list and how to make up an ethernet transceiver cable. AMP part no. 745652-2 pin kit AMP part no. 745583-5 matching slide lock kit AMP part no. 206514-1 metallic hood (right-angle, need 2) DA15P D-15 shell (solder type) DA15S D-15 shell (solder type) Belden cable no. 9891 transceiver cable, 4pairs 20AWG (alternate: Alpha no. 9853) [Amphenol has parts equivalent to the AMP ones, I don't know the exact part numbers. Also, cable from Consolidated and other cable shops work as well.] The pin kit and one hood goes on the male D-15 shell. The slide lock kit and the other hood goes with the female D-15. All wires in the cable go "straight across" (e.g., pin 10 on the male to pin 10 on the female, etc.) The active connections are: one pair: pins 3, 10 one pair: pins 5, 12 one pair: pins 2, 9 one pair: pins 6, 13 (if one pair is heavier gauge use it here; this is the power pair, usually coded black & red, supposedly PVC [vice FPP] insulated, sometimes heavier gauge.) The outer shield of the cable gets connected to pin 1, hood and shell (i.e., short it out against the shell, as well as pin 1). That's all there is to it for Ethernet v.1 & v.2, except that if the cable has a separate inner shield, that should be in contact with the outer shield as well. For an IEEE 802.3 cable, there are supposedly two separate shields in the cable: an inner shield and an outer shield. The inner shield is supposed to be connected to pin 4, while the outer shield. This may be trivial, since cables wired in the old way (without the separate inner shield and its pin 4 connection) seem to work just fine. -- Bob Cunningham bob@hig.hawaii.edu
eshop@saturn.UUCP (09/19/87)
We evaluated several kinds of transciever cable and ended up selecting Manhatten 4190. We like this cable because it is signifcantly more flexible than transceiver cable that has two shields. We hook the drain wire up to both pins 1 & 4. To get a tight fit between the braid and the clamp on the hood, we fold the braid back on top of the PVC jacket, leaving enough jacket to extend into the area that is clamped. We built a pair of boxes that we connect to either end of a transciever cable. One pulses the eight wires, each at a different rate. The other box has eight light emitting diodes. We use these to assure ourselves that all wires are connected and in the right order. The reason for this paranoia is that a transciever cable that has a problem with the collision detect pair will appear to work but the computer will not be able to detect collisions. Finally, it is important that you stress to your technicians that the pairing of the wires is extremely important. Noise immunity in xcvr cables comes from the three signals being transmitted differentially. If you get the wires paired wrong you could created problems from cross talk that would be very hard to diagnose.