CHAPTER 3: Getting Started
+VTEST | GND +VTEST RTS CTS -TXD -RXD |
Figure 3-16. Rear View of the Interface Converter’s Serial Connector.
-RxD | Receive Data—Input—Pin 2 |
This pin accepts serial data sent by the RS-232 or RS-422 host. The serial data is expected with the word length, baud rate, stop bits, and parity selected by the internal switches. The signal level is low true.
-TxD | Transmit Data—Output—Pin 3 |
This pin transmits serial data to the RS-232 or RS-422 host. The serial data is sent with the word length, baud rate, stop bits, and parity selected by the internal switches. The signal level is low true.
CTS | Clear To Send—Input—Pin 4 |
The CTS input is used as a hardware-handshake line to prevent the interface converter from transmitting serial data when the RS-232 host is not ready to accept it. When RTS/CTS handshake is selected on the internal switches, the interface converter will not transmit data out -TxD while this line is un-asserted (lowered). If the RS-232 host is not capable of driving this line it can be connected to the Vtest output (Pin 6) of the interface converter. If X-ON/X-OFF handshake is selected, the CTS line is not tested to determine if it can transmit data.
RTS | Request To Send—Output—Pin 5 |
The RTS output is used as a hardware handshake line to prevent the RS-232/RS-422 host from transmitting serial data if the interface converter is not ready to accept it. When RTS/CTS handshake is selected on the internal switches, the interface converter will drive the RTS output high when there are more than 1,000 character locations available in its internal buffer. If the number of available locations drops to less than 1,000, the interface converter will unassert (lower) this output. If Xon/Xoff handshake is selected, the RTS line will be permanently driven active (high).
