88
Serial and TCP Protocols
like Tx and Rx. RTS is an output for a DTE, and tells the DCE whether or not it is willing to accept data.
CTS is an output for DCE, and tells the DTE whether it is able to accept data.
Thus:
In the null-modem cable, RTS and CTS are also swapped over:
Two additional modem control lines were defined to signal the overall readiness state of the attached
devices. These lines, DTR (Data Terminal Ready) and DSR (Data Set Ready i.e., modem ready) are less
important than RTS/CTS, but are nevertheless used often.
The wiring for these is:
And in the null-modem cable, the DTR/DSR pair also crosses over quite
naturally:
DTE
Tx
Tx
Rx
Rx
GND
GND
DCE
RTS
RTS
CTS
CTS
5-Wire Straight-Through
DTE
Tx
Tx
Rx
Rx
GND
GND
DTE
RTS
RTS
CTS
CTS
5-Wire Null-Modem
DTE
Tx
Tx
Rx
Rx
GND
GND
DCE
RTS
RTS
CTS
CTS
DTR
DTR
DSR
DSR
5-Wire Straight-Through
DTE
Tx
Tx
Rx
Rx
GND
GND
DTE
RTS
RTS
CTS
CTS
DTR
DTR
DSR
DSR
7-Wire Null-Modem
Содержание EM1500
Страница 14: ...10 www rabbit com Introduction...
Страница 22: ...18 www rabbit com Getting Started...
Страница 76: ...72 www rabbit com EM1500 Configuration...
Страница 90: ...86 www rabbit com EM1500 Specifications...
Страница 104: ...100 www rabbit com Serial and TCP Protocols...
Страница 118: ...114 www rabbit com EM1500 FAQ...