ADLINK Technology CM1-86DX3, Technical Reference, Page: 30 / 59

24 Interfaces
Note : The shaded table cells denote power or ground. The * symbol indicates the signal is Active Low.
Table 3-1: Serial Port 1 (CN16) & Port 2 (CN14) Interface Pin Signals
Pin # Signal DB9 # Description
1 DCD*
TX-/RX-
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.
If in RS-422 mode, this pin is TX- (Data Negative). If in RS-485 mode, this
pin is TX-/RX- (Data Negative).
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
TX+/RX+
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.
If in RS-422 mode, this pin is TX+ (Data Positive). If in RS-485 mode, this
pin is TX+/RX+ (Data Positive).
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
RX+
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.
If in RS-422 mode, this pin is RX+ (Data Positive).
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*
RX-
4 Data Terminal Ready – Indicates serial port is powered, initialized, and
ready. Used as hardware handshake with DSR for overall readiness.
If in RS-422 mode, this pin is RX- (Data Negative).
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