A data transfer control system includes: a port control section which controls ports P1 and P2 respectively connected with an electronic instrument PC1 and an electronic instrument PC2; and a bus reset issue section which issues a bus reset. The port P2 is set to a disabled state, and then the bus reset is issued to cause the electronic instrument PC1 to acquire an access right. The port P2 is set to an enabled state after the bus reset has been issued and the electronic instrument PC1 has acquired the access right. After the electronic instrument PC2 has been detected to be in a suspended state, a resume packet is transferred to the electronic instrument PC2. The port P2 is set to a disabled state after the power for the data transfer control system has been turned on.