I was looking for a wireless system for those occasions when there is no hill wire in place. I like the WTN network because it utilizes a mesh network (802.15.4 to be specific). A mesh system overcomes the problem of not having line of site on a ski hill by allowing you to place relay radios at all the high points along the trail.
So we purchased a pair of WTN "yellow" boxes and a set of PR1aW (Wireless) photocells. If I had a Timy or TDC8001 I would connect the WTN to the timer using the 25-pin D-sub connector. But no such luck, I use Tag Heuer PTB605s. However the WTN can still be used as an impulse transmit provided that you have some free time and a soldering iron. So I threw together a quick adapter that routs the impulse pins on the D-sub to some banana-jacks that I had. Note that the WTN adds a constant 0.1s delay to allow the impulse to propagate through the mesh network and you will lose the impulse "retransmit" functionality. So to be safe you should directly wire some backup timers at the photocells/start gates to be safe. You can see the final product in the attached picture.