It's an old thread, but I recently repaired a couple of Turbo Express units and picked up a second copy of Bomberman '93. I really wanted to do the multiplayer thing with my kids on the road.
The good news:
Standard stereo headphone jack cables work as com cables. (I think they're 1/8in mini jacks?)
The bad news... really, really bad news:
Bomberman '93's com multiplayer mode is a JOKE. You hook up, one person is black, the other is white. No options for computer players. You pick the number of trophies, and off you go. No choice of map. Up to this point I was just a little bummed... but after the third round with my 7 year old, he said, "Dad, why are the items in the same place every game?" ... and I realized...
The map, block location, power-up locations, skull locations... everything is the SAME EVERY ROUND.
Then I thought, ok, what happens at the end of the game and a new game is started? SAME MAP.
What if we turn off the units and resync? SAME MAP.
The Bomberman '93 game has one com link map and one map only. It is the exact same every single round.
Unbelievable. I'll have my second Express, second Bomberman '93, and "Com Link" cable up on Ebay shortly. ;-)