SENA DirectPort UPCI Software - Manual (Page 18)

18
Slew Rate Limit reduces reflected waves emitting from ends of communication
cables and speeds up slew-rate driver that restrains EMP electromagnetic
waves thereby enabling communication with no data errors. But communication
speed is limited in this mode
7.3 Cabling
7.3.1 RS422 Point-to-Point Connection
7.3.2 RS422 Multi-Drop Connection
7.3.3 RS485 Connection
RT: 120 Ohm (Not necessary when there is not much noise)
RS485, like LAN, uses Half Duplex Bus and has no classification between
host and terminal
TXD+
Host
Terminal
RXD+
TXD-
RXD-
RXD+
2
3
6
7
3
2
7
6
TXD+
RXD-
TXD-
TXD+
Host
Terminal
Terminal
RXD+
TXD-
RXD-
RXD+
2
3
6
7
3
2
7
6
2
3
6
7
TXD+
RXD-
TXD-
RXD+
TXD+
RXD-
TXD-
R
T
TRXD+
3 7 3 7 3 7
TRXD- TRXD+ TRXD- TRXD+ TRXD-
R
T
Terminal Terminal Terminal