Often appears in the journalistic phrase
信息灵通人士 (xìnxī língtōng rénshì, 'well-informed sources') — the Chinese equivalent of 'sources close to the matter'.
灵通 means 'having quick channels of information', so the whole phrase reads 'information-channels are quick'. Compare with the synonym
消息灵通 (xiāoxi língtōng).