Deaf climbers and hearing climbers with Deaf partners are not the only ones that can benefit from this "No-Voice" multi-pitch communication system. Hearing climber teams may benefit as well. Many accidents occur from misunderstanding verbal commands shouted a pitch away, especially in windy conditions or on crowded crags with many voices mingled together.
Disclaimer: Rock climbing and mountaineering is a dangerous and technical sport. This is not an instructional guide. Seek proper and professional instruction.
Silent Multi-Pitch Climbing Communication when the leader and second are out of both sound and sight range:
If climbers are within sight range, predetermine ARM signals with your partner. Hand signals are too small and can be easily misinterpreted... From a pitch away, a thumbs up or fist motion look the same
1. The leader climbs, builds anchor at top of pitch and clips in. Set up belay device in guide mode (or preferred belay method) but do not thread rope through the belay device yet. Pull up the rest of the rope.
2. The second does not take the leader off belay, even if the second suspects the leader is safely clipped to an anchor. Continue to feed the rope through the belay device.
3. When the leader suspects the end of the rope has been reached (usually indicated by the verbal command from the second: "that's me" ), let out a some slack and pull tight. This helps ensure it's not just rope drag or a pinched rope. Put the rope through the already prepared belay system and put the second on belay.
4. A few feet before the leader's rope pulling reaches the end of the rope (the second's harness), the second holds the rope taunt for the non-verbal "That's Me" command. Wait 10 seconds for the leader to put the rope through the belay device. The second releases a few inches of rope at a time. If the rope continues to tighten, you are on belay. This technique is especially reassuring for hanging belays where breaking down the anchor before the belay is on could have very bad results!
Regarding rope tugs:
Some people like to incorporate rope tugs for communication. I personally prefer not to rely on this method since wind and rope drag may influence rope tug perception. Additionally, the leader clipping the rope may feel similar to the common " tugs for off/on belay" that some climbers use. Also, rope tugging could potentially knock down loose rock. As I mentioned before, my voice-less multi-pitch communication system is just a base system to use. If you feel it is necessary to add rope tugs, discuss with your partner and use at your own discretion.
Be safe and climb on!