Nach wiederholten Diskussionen hier ein Auszug aus Wikipedia zum Thema Handzeichen:

"Generally, a closed fist means the player will not attempt a block, one finger means the player will attempt to block an opponent's spike down the line, two fingers means the player will attempt to block an opponent's spike into the angle, and an open hand means the player will block "ball," deciding where to set the block based on the set and on the opponent's approach and arm-swing. Wiggling the fingers on one of the signalling hands indicates that the blocker wants his or her partner to serve the player on that side of the court. If the server is a stronger blocker, he or she may run up to the net to block after serving. In this case, the signals given by the server's partner tell the server what type of block to put up."