RS 232 Communication Problem

I've built a RS232 receiver and transmitter.. I've tested it by sending some 64 bit data(multiplexed as 8 bits) through TxD and routing it back to RxD and read is using same monitoring software through which I've sent the data.. The problem is I'm getting a continuous loop of data, that too only the last symbol(last 8 bits of the multiplexed data)..... I want only the 64 bits to be displayed.... The symbol need to be sent only once... What should I do??