something I've always wondered

Does DES (or name your favorite encryption algorithm) produce as output all possible cyphertexts of length L, given all possible conbinations of keys and plaintexts of length L? Since there are more combinations of key and plaintext than there are possible cyphertexts outputs of length L, you know there must be some combinations of key and plaintext that produce the same cyphertext. Just curious, Jim_Miller@suite.com