this mode is used in applications where the ir-x.21 b side uses the clock signal from the modem link. this mode is used mainly when the attached equipment has an ir-x.21 interface, but no ability to produce clock signals. the module has two 16-bit fifo's buffers to compensate for the phase delay introduced by the x.21 device.

    figure e-5 illustrates the buffers connection and the required application setup. when the modem's clock mode is int or rcv, the jp2 jumper must be set to int/rcv (see figure e-3).