TELCO SYSTEMS INC <TELC> 2ND QTR MARCH ONE LOSS Shr loss nine cts vs profit 14 cts Net loss 773,000 vs profit 1,618,000 Revs 16.3 mln vs 26.7 mln Six mths Shr loss 56 cts vs profit 27 cts Net loss 4,763,000 vs profit 3,398,000 Revs 29.3 mln vs 49.9 mln