Multiple 8X2A/ev's may be cascaded serially to operate from the same
serial port.  The first step is to assign each 8X2A/ev an ID (password).
The second step is to remove two components from the receive side of the
serial port.
Follow the steps below:

        1 - Remove the four top cover screws from the 8X2A/ev.
        2 - Remove the cover.
        3 - Lift one side of R-116 and D-23 by heating the junctions
            with a soldering iron.
        4 - Test each unit and return the top cover to each unit.

Purchase an RJ-11, 6P6C T-adapter reverse wiring adapter from Radio
Shack or your local Telecom dealer.  If more than two units need to be
cascaded, Radio Shack makes a five position adapter.  Remember that by
removing the two components listed above, the serial status is disabled.
To monitor the silence sensor with the serial status disabled, one must
use some other digital input to monitor the open collector of the
silence sensor.