User guide

WA_DEV_FEX20_UGD_002 Rev 004 March 08, 2011 40
Fastrack Xtend User Guide
Interfaces
5.1.2.1. RS232 Serial Link Connection
Also known as the main serial link, the RS232 interface performs the voltage level adaptation
(V24/CMOS ⇔ V24/V28) between the internal Fastrack Xtend (DCE) and external applications (DTE).
The signals available on the RS232 serial link are as follows:
 TX data (CT103/TXD)
 RX data (CT104/RXD)
 Request To Send (CT105/RTS)
 Clear To Send (CT106/CTS)
 Data Terminal Ready (CT108-2/DTR)
 Data Set Ready (CT107/DSR)
 Data Carrier Detect (CT109/DCD)
 Ring Indicator (CT125/RI)
Figure 16. RS232 Serial Link Signals
The RS232 interface has been designed to allow flexibility in the use of the serial interface signals.
However, the use of TXD, RXD, CTS and RTS signals are mandatory; while the use of DTR, DSR,
DCD and RI signals are optional.
Tip: The Fastrack Xtend is designed to operate using all serial interface signals and it is recommended
to use CT105/RTS and CT106/CTS for hardware flow control in order to avoid data corruption
during transmission.
The Fastrack Xtend also implements the Serial Port Auto Shut Down feature with the DTR signal. It
is recommended to use the CT108-2/DTR signal to benefit from the current consumption
improvement performed by this feature.