Black Box IC171C - Manual (Page 15)

10
RS422/485 SERIAL INTERFACE PLUS
Figure 4-4. Header E2 in Shared Mode.
Header E5 is used to control the RS-485 enable/disable functions for the
driver circuit. One of the unique features of the RS422/485 Serial Interface
Plus is its ability to be RS-485 compatible without the need for special software
or drivers. This is especially useful in Windows, Windows NT, and OS/2
environments where the lower level I/O control is abstracted from the
application program. This means that the user can effectively use the
RS422/485 Serial Interface Plus in a RS-485 application with existing software
drivers.
Figure 4-5. This jumper is in the “422” position. Note that the modem
control outputs are only valid when Header E5 is in the 422 mode.
AUTO Driver automatically Enabled/Disabled
RTS Driver Enabled by UART RTS signal
422 Driver always Enabled
Figure 4-6. Header E5.
N
RTS AUTO 422
TX
N
S
S
M
M