THE PRESENCE of an American team at the world table-tennis matches in Pyongyang, Communist North Korea, suggests a replay of the "ping-pong diplomacy" that culminated in the normalization of relation between the United States and China.But it isn't that way at all. North Korea invited the American team, and since the Carter adminstration had abandoned the controls formerly imposed on private travel to countries with which the United States has no ties, the American players were free to go. They went. Cravenly, the International Tennis Team Federation did not demand that North Korea invite all members. South Korea was excluded by political chicanery and Israel on the specious grounds that North Korea, perhaps the world's tightest police state, could not ensure the team's security.

Pictures of American and North Korean playets embracing each other after a match have been circulated. Again, the impression is misleading. No warmth exists, or seems likely to soon, in American-North Korean relations. Washington has long refused to undercut its South Korean ally and deal directly with its North Korean adversary; it wants the South Koreans to be in on any talks. The two Koreas have recently made an attempt, not their first, at "dialogue," and it has gotten nowhere. Jimmy Carter during his campaign, suggested the time was ripe for a unilateral withdrawal of the 44,000 American ground troops that have been in South Korea since the armistice of 1953, and this caused a major stir. Wisely, he later found cause - partly in new estimates of North Korean strength - to suspend the withdrawal. It is one of the questions he will look into when he visits Seoul next month. Human rights is another.

Yet a third false impression - of North Korea humanitarianism - was conveyed by news reports of the reuniting of the American team's North Korea-born interpreter with his mother in Pyongyang; he had fled south in the Korean war and they had not seen each other in 29 years. This may have been only the second time North Korea has allowed one of its citizebs even a momentary encounter with a relative who fled south. To appreciate this it helps to keep in mind that literally millions of Koreans belong to families separated by the 38th parallel. South Korea has given top priority to negotiating family reunions, starting with the sharing of family information and the opening of mail and phone links. The north, beyong two or possibly three token meetings, has not given an inch. In this fundamental sense, it is the cruelest country in the world.