Serial Port Setup

Connecting the Serial Ports

The RS232 serial port on the Accelerated 635x-SR provides two modes of functionality:

  1. Login - provides login access to the 6350-SR itself.
  2. Remote access - Remote OoB access to the console of another client device.

By default, the 635x-SR's serial port operates in the Login mode.

You must use a cable with an RJ45 connector to connect to the 635x-SR with a RJ45, DB9F or DB9M connector, as determined by your device type, to terminate to your device. Consult the user guide for the device you are connecting to the 635x-SR to determine the connector type, cable type, and pinout positions for your specific device.

The serial port is enabled by default. 

If the 635x-SR's serial mode is set to Remote access, the network device connected to the 635x-SR's serial port may be accessed using the Accelerated View terminal window, the 635x-SR's local web GUI, TCP, telnet, or SSH connections. TCP, telnet and SSH connections to serial ports are disabled by default and must be enabled by a device specific configuration. Connect the network devices to the Accelerated 635x-SR's serial port using the pinout information below.

Serial Port Pinout and Use

The RS232 standard requires support for baud rates up to 9600 baud on shielded multicore cable up to 50 feet (15 meters) long. For the 635x-SR, the use of standard CAT 5 cables enables serial communication at all baud rates up to 50 feet. CAT5 unshielded twisted pair cable lengths much longer than 50 feet have been verified at 9600 baud but are non-standard and are not guaranteed.

The 6350-SR's RS232 serial port is DTE and has the following pin configuration.

Pin 1 CTS Clear to send
 Input to 635x-SR
Pin 2 DTR Data terminal ready
 Input to 635x-SR
Pin 3 TXD Transmit data Output from 635x-SR
Pin 4/5
Ground Signal ground
Pin 6 RXD Receive data Input to 635x-SR
Pin 7 DCD Data carrier detect Output from 635x-SR
Pin 8 RTS Request to send Output from 635x-SR

NOTE: ring indicate (RI) and data set ready (DSR) are not implemented

The serial ports use a female RJ45 jack to enable connection using UTP Ethernet cabling.

Wiring for remote access (out-of-band)

The serial port of the 635x-SR has the same pinout as most common router console ports.  Therefore, it is recommended to use a rollover Ethernet cable if the 635x-SR's serial mode is set to Remote access, since the pins have to be reversed in order to provide remote access into a secondary router's console port.

USB-to-Serial Access

In addition to the dedicated RS232 serial port, serial out-of-band (OOB) access can be leveraged over SSH using the USB port.

For assistance with enabling SSH, please refer to the following documentation:

This feature is currently supported by shell interactions in an SSH session. With shell access enabled, press 's' after authenticating to the device.

$ ssh [email protected]
$ password
Access selection menu:         
                               
    a: Admin CLI               
    s: Shell                   
    q: Quit                    
                                
Select access or quit [admin] : s
Connecting now, 'exit' to disconnect from shell ...
#
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The relevant command(s) for USB-to-Serial access will depend on the type of adapter being used.

Single USB-to-Serial Cable

Purchasing options are available through Accelerated. Refer to the following command to bring up a single serial connection over USB. 

tip -l "$(dmesg | grep "FTDI USB Serial Device converter now attached" | grep -o "ttyUSB[0-9]")" -c
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USB-to-Serial Splitter

Purchasing options are available through Accelerated.

To conveniently access multiple serial connections over SSH using this adapter, enter the following script into router's Custom Script field, setting its Run mode to "On boot." This field is nested under System > Scheduled Tasks > Custom Script.

cat <<EOT > /opt/serial_port_selector
#!/bin/sh
bugout() {
  echo "\$@"
  exit
}
serials="\$(dmesg | grep "FTDI USB Serial Device converter now attached" | grep -o "ttyUSB[0-9]" | sort -u)"
[ "\$serials" ] || bugout 'no serial-to-USB converters found'
serial_count=\$(echo "\$serials" | wc -l)
echo "Found \$serial_count USB-to-serial converters."
for i in \$serials; do
  echo "\$i"
done
echo "Type the number of the USB port you wish to open a console connection to"
echo "(e.g. for ttyUSB2, type '2'), followed by ENTER:"
read port_num
serial_port=\$(echo "\$serials" | grep "\$port_num")
[ "\$serial_port" ] || bugout "Port number \$port_num is not available, please re-run and specify a differnt port."
echo "Opening connection to USB-to-serial port \$serial_port."
echo "Press '~.' followed by ENTER to close connection."
tip -l "\$serial_port" -c -s 9600
EOT
chmod +x /opt/serial_port_selector
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With the script enabled, SSH onto the device and enter the following command from the shell to bring up the available serial connections:

/opt/serial_port_selector
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This will list all available connections. Enter the number of the USB port to proceed. For example:

Access selection menu:
    a: Admin CLI           
    s: Shell               
    q: Quit                
Select access or quit [admin] : s
Connecting now, 'exit' to disconnect from shell ...
# /opt/serial_port_selector 
Found 4 USB-to-serial converters.
ttyUSB0
ttyUSB1
ttyUSB2
ttyUSB3
Type the number of the USB port you wish to open a console connection to
(e.g. for ttyUSB2, type '2'), followed by ENTER:
3
Opening connection to USB-to-serial port ttyUSB3.
Press '~.' followed by ENTER to close connection.
Connected.
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