An information flow control device has: a first network interface card on a transmission side, the first network interface card including first and second transceivers, each of the first and second transceivers having a transmit port and a receive port; and a second network interface card on a receiving side, the second network interface card including at least one receive port. A first data connection segment connects the first transceiver transmit port to the second transceiver receive port, a second data connection segment connects the second transceiver transmit port to the first transceiver receive port, and a third data connection segment connects the first transceiver transmit port to the receive port of the second network interface card. The first and second segments provide continuity, while the third segment provides one-way data transfer. The first and second transceivers are replaceable with third and fourth transceivers to provide different throughput.