ADLINK CoreModule 435 - Manual (Page 31)

Chapter 3 Hardware
CoreModule 435 Reference Manual 25
Note: The shaded table cells denote power or ground. The * symbol indicates the signal is Active Low.
Table 3-6. Serial Port 3 (J14) & Port 4 (J13) Interface Pin Signals
Pin # Signal DB9 # Description
1 DCD* 1 Data Carrier Detect – Indicates external serial device is detecting a
carrier signal (i.e., a communication channel is currently open). In direct
connect environments, this input is driven by DTR as part of the DTR/
DSR handshake.
2 DSR* 6 Data Set Ready – Indicates external serial device is powered, initialized,
and ready. Used as hardware handshake with DTR for overall readiness.
3 RXD 2 Receive Data – Serial port receive data input is typically held at a logic 1
(mark) when no data is being transmitted, and is held “Off” for a brief
interval after an “On” to “Off” transition on the RTS line to allow the
transmission to complete.
4 RTS* 7 Request To Send – Indicates serial port is ready to transmit data. Used as
hardware handshake with CTS for low level flow control.
5 TXD 3 Transmit Data – Serial port transmit data output is typically held to a
logic 1 when no data is being sent. Typically, a logic 0 (On) must be
present on RTS, CTS, DSR, and DTR before data can be transmitted on
this line.
6 CTS* 8 Clear To Send – Indicates external serial device is ready to receive data.
Used as hardware handshake with RTS for low level flow control.
7 DTR* 4 Data Terminal Ready – Indicates serial port is powered, initialized, and
ready. Used as hardware handshake with DSR for overall readiness.
8 RI* 9 Ring Indicator – Indicates external serial device is detecting a ring
condition. Used by software to initiate operations to answer and open the
communications channel.
9 GND 5 Ground
10 Key/NC NC Key Pin – Not connected