I have climbed for many years with different people and have never come across a good system for communicating Belay commands (Leader or the 2nd) if you can't hear one another.
Are there any reliable or "standard" belay commands that can be used if voice commands can't be recognized?

I've climbed with several partners that use "rope pulls" to communicate.
Off belay=pull up 15' of extra rope and drop it three times in a row.
Belay on=three sharp pulls of the rope.

If you hear: "Aw Shit!!!" -- hold the rope.

I use 4 big ass tugs.

There was a previous forum discussion on this a while back (maybe someone else will post that link, I don't recall when it was brought up). From that, I took some people's suggestions. If your partner is leading, and you're not sure he/she really said "off belay", you can continue to feed the rope through your belay device until it reaches the end. I've done this a couple times, and probably have annoyed my partner at the slowness of feeding the rope through (eventually you become pretty sure they're off as it feeds continually), but I feel better as the belayer not taking them off unless I'm absolutely certain they're anchored in. And like Larry said, once the rope is out, and a couple minutes have passed, I'd start climbing a short distance and check that my partner is taking in the slack.

One of my partners and I agreed last weekend that when we were leading, we'd have the other person on-belay within a minute or two of pulling up the rope. So if we needed more time after reaching the belay station to get comfy, eat, drink, pee, or what not, we didn't pull the rope up until after taking care of all that. Seemed to work well.

Rope tugs for me too: 3 for on, 3 for off. I've used this system for several years now after many more years of yelling. I wish someone had hipped me to rope tugs when I first started climbing. Possibly not good for a pure newbie, but for an experienced team it is pretty much fool proof. You can always yell if you have to, but for 99.999% of your pitches you'll never need to shout again. And let me say this - the "but what about rope drag" argument is purely academic. If you have so much rope drag that your partner can't feel the tugs, the rope is completely stuck and you have another sort of problem, anyway - just start yelling.

I have tried, mostly in vain, to get my partners switch to the Canadian system... use the word "secure" when you reach the belay. This eliminates the leader yelling "off belay" and then, two minutes later, yelling "on belay".
However, most people don't want to shift simply cus they are cattle (Hans)!

BTW, I'm not a Canook... I just lived up there for 4 years and after just a little while of living with the "secure" command I realized how much it helped with the confusion.

In all other aspects.... tugs work... unless there is really bad drag.

I agree with Sam - I hate using "off belay," because it sounds so much like "on belay." I've switched to using "secure" as well.

However, the original question was what to do when you can't hear each other. I've used the rope tug method, but I admit it's less than ideal.

I've always been amazed that there isn't a better standard for the on/off belay when you can't hear each other.

I've used the 3 rope tugs, but usually do 3 tugs, followed by a pause and another 3. Kind of confirmation I suppose and the second three are "yep this isn't I need slack and there is rope drag."

One problem we've run into is that sometimes the first tug is mistaken for "give me slack damnit!" So slack is given by the belayer and then it is hard to notice the other tugs with all that rope out.

When in doubt I totally agree that you just keep them on belay and feed all the rope through the belay device. As pointed out already, at least you are simul climbing with no slack between you rather than mistakenly taking someone off lead.

Someone always points out "hey I use radios" Which are great and have their place, but even then it is nice to have a system if you drop one or the battery dies.

I climbed once with a partner who said "safe" I could NEVER tell if it was "safe" or "slack" but couldn't get her to change to something else. I ended up just belaying all the rope out every time. "Secure" sounds pretty good. Though I'd still vote for something that doesn't start with S and can't be confused with "take, slack or OH SHIT FALLING"

I prefer "secure" over "off belay" or "belay off" too.

My command for "on belay" when I can't hear or see my partner is three strong tugs on the rope, pause, three strong tugs. No off switch.

Seems to work ok.

-Brian in SLC

sweet headsets...does it come with a free gun?

good point Brian. Why take yourself off-belay if your belayer can't hear you. It isn't that much slower to just feed rope through the belay device. No mishaps then.

It sounds like the consensus is rope tugs. I've used radios before but I agree they are not 100% reliable. Rock on my climbing friends