If people inhabit Mars, what means of communication between two planets might be fast enough to share useful information?

What is Mars??

Mars is the fourth planet from the Sun and is the second smallest planet in the solar system. Named after the Roman god of war, Mars is also often described as the “Red Planet” due to its reddish appearance. Mars is a terrestrial planet with a thin atmosphere composed primarily of carbon dioxide.

How does the Mars base communicate with Earth?

All communication between Mars and Earth goes through satellites. Because of the distance, there is a substantial delay. As communication signals travel at the speed of light, this means that it can take between 3 and 22 minutes for the information to reach the other end, so a phone call would not be practical. Fortunately, there would be no limitations to email, texting or 'WhatsApping' with the Mars residents. It'll just take at least 6 minutes for you to get your reply. Both voicemail and video messages are also easily workable options.

X-band radio waves used by the rover to communicate

The rover communicates with the orbiters and the DSN through radio waves. They communicate with each other through X-band, which are radio waves at a much higher frequency than radio waves used for FM stations

The radio waves to and from the rover are sent through the orbiters using UHF antennas, which are close-range antennas that are like walkie-talkies compared to the long range of low-gain and high-gain antennas.

When the rover speaks directly to Earth (from the surface of Mars), it sends messages via its high-gain antenna (HGA). The high-gain antenna can send a "beam" of information in a specific direction and it is steerable, so the antenna can move to point itself directly to any antenna on Earth. The benefit of having a steerable antenna is that the entire rover doesn't necessarily have to change positions to talk to Earth. Like turning your neck to talk to someone beside you rather than turning your entire body, the rover can save energy by moving only the antenna.

We can use these methods to communicate people on mars until new methods of communications are introduced.