  An experiment to measure an invariant mass of {\phi} mesons in nuclear medium
is planned as the J-PARC E16 experiment. A trigger merging module (TRG-MRG) has
been developed to detect leading-edges from 256 channels of
discriminator-output signals and transmit those serialized hit data to trigger
decision module with four optical links. The result of the test shows enough
performance of the TRG-MRG as 1 ns TDC and data multiplexer with four 6.25 Gbps
transceivers.
