A communication system uses multiple communications links, preferably links that use different communications media. The multiple communications links may include a high latency/high bandwidth link using a fiber-optic cable configured to carry large volumes of data but having a high latency. The communications links may also include a low latency/low bandwidth link implemented using skywave propagation of radio waves and configured to carry smaller volumes of data with a lower latency across a substantial portion of the earth's surface. The two communications links may be used together to coordinate various activities such as the buying and selling of financial instruments.