I am doing load balancing on my rb 493 ah, voip does not work. calls are not going out.
i think the problem is with the load balance.
por favor give me suggestions on what to do.

So based on your message, I'll assume you disabled load balancing to see if the VoIP started working. I'll also assume you are using SIP protocol.

If you load balance across more than one Internet connection, you have to ensure all the VoIP traffic stays on one. The issues are:

1) The SIP protocol is UDP (or sometimes TCP but usually not) on port 5060 and is only call control. The audio portion is UDP (should never be TCP) and runs on other ports which are dynamically selected. Most SIP devices end up behind NAT, so when a SIP device tells another SIp device you can send you audio to 192.168.5.24:5008 it won't work through the NAT. This is normally dealt with by ignoring the IP address the device told me to send the audio to and substituting the IP address from which the UDP came (the address replaced by the NAT code on the firewall). This further assumes the originating SIP device has opened a NAT pinhole by sending UDP to the other SIP device early on in the session (you can see all the "pinholes" opened by looking at the Connection Table in winbox). So, if your load balancing sends the RTP audio out the "wrong" or "other" Internet connection as compared to the SIP traffic, the whole thing breaks.

2) When your SIP device registers with a SIP proxy on the Internet, the SIP proxy will assume is can always talk back to the SIP device on the originating IP address and port. In fact, the SIP proxy may "ping" the SIP device to keep any NAT pinhole open. Load balancing can get in the way of this as well.

Your easiest solution is to policy route all the SIP devices out a single Internet connection. If the connection goes down, you can have the route switch over but remember that all ongoing calls will break down in that case and the SIP devices will all have to reregister using the new route (and thus the new or other IP address) before calls will arrive.

Its there any chance you could explain how its done.
how to send the traffic through one of the dsl lines.
I am new at using mikrotik, I managed to get load balancing on. thank to the help of a IT in mexico city. But i cant get a voip call out.
My clients are getting upset

I can help some. First, disable whatever you're doing for load balancing now and see if the problem goes away. If so, then I would next move to a static load balancing since you said clients I assume you can route client A out connection 1, client B out connection 2, client C out connection 1, and so on. If you are NAT'ing for all your clients, this is easy to do with a couple of different Src-Nat statements to different public IP's and removing any Masq NAT. If you are routing public IP's to clients, then this can be done with policy routing which you will need to get a good handle on to go further anyway. Look in the WiKi for help with policy routing.

Dynamically load balancing multiple clients across multiple Internet connections while trying to deal with protocol issues brought up by things like SIP, P2P, and various IM systems is really hard. You need to master NAT, Policy Routing, & Mangling AND you need a really good handle on the protocols mentioned above.