It means not enough communication. For example like poor communication skills mean that you are not good with communicating with people.

In a military situation it can also mean that they cannot send messages easily via radio or other means.

http://bookboon.com/blog/2014/06/10-signs-poor-communicator/ please visit the link u will know the best details about the Poors Communications and its types... and also keepnin minds mostly the means are depends on situations ... For me its means ... Didn't Talk Properly... but u must go to the link and read the article.!

thank you, Richard.

Poor communication can include "not communicating often enough or seriously enough, or communicating in a wrong, bad, disrespectful, impolite, untruthful, or inappropriate manner." So, your understanding of the expression is correct.