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Quick Start Guide

VAYU2 - RevA Quick Start Guide [PDF]

Jumper Details

User can select the RS232 Communication ports Serial Port-1 or Port-2 by using the Jumper J7. Serial Port 1 is the UART1 of the Beaglebone CPU and Serial Port 2 is the UART2 of the Beaglebone CPU.


Getting Started

Setting up the system

  1. Place a micro-SIM in the SIM card slot and connect a respective antennas to the SMA connectors.
  2. Mount the VAYU2 cape on Beaglebone Black.
  3. Ensure the power jumper J1 with all other jumpers according to your application use are in place.
  4. Connect the extra USB cable provided with the cape between Host port on Beaglebone Black and miniUSB device port on Cape.
  5. To avoid the bug on Beaglebone black with external USB hubs, please connect a USB device (Pendrive etc.) to extra host port on the cape.
  6. Now power up the full setup using a 5V DC adapter(min 2.5A) to barrel jack. D2 LED on the cape will glow along with LEDs on the Beaglebone black.
Note: Before powering up ensure correct software image is loaded in Beaglebone black or VIBE/VIBE2

Before proceeding further ensure D2 LED is glowing properly. Make sure that the adapter being used is of proper rating and has been connected properly.

Do not try to power up using USB cable alone. Always power up system with a DC adapter. Also while disconnecting power, USB cable should be removed before the DC adapter.

Accessing the System

  • Through USB

For accessing the above setup, first connect the USB cable between Beaglebone Black's USB Client port and USB Host port of Desktop/Laptop. Once it get properly connected to Desktop, a user can access the setup using predefined static IP address

On Windows : (Using Putty Client)

On Linux :

ssh root@

Default password is root.

  • Through Ethernet

In Yantrr Pre-compiled images, the Ethernet IP address is set to static IP If you are using DHCP IP then Ethernet IP be should be know and the same should be used while making ssh connection.

On Windows : (Using Putty Client)

On Linux :

ssh root@

Default password is root.

Modem Ports

VAYU2 has an option between 3G/HSPA+ and 4G/LTE,CAT4 modem for WAN connectivity.

  • 3G Modem : VAYU2 3GUC20-x comes with Quectel UC20 3G modem.
  • 4G Modem : VAYU2 4GEC25-x comes with Quectel EC25 4G modem.

Both 3G/4G modem creates 5 ports :

  1. /dev/ttyUSB0  : DM
  2. /dev/ttyUSB1  : For GPS NMEA message output
  3. /dev/ttyUSB2  : For AT commands
  4. /dev/ttyUSB3  : For PPP connections or AT commands
  5. /dev/cdc-wdm0  : QMI WWAN Port

Modem Control

Please ensure that the modem is properly turned on before ppp connections can be established. If PPP connection cannot be established properly, soft reset the modem following the timing procedures for modem.

The modem can be powered on/off by either using the push button switch or GPIO45.

Power on

The module will be turned off after power-on(when power is supplied) normally. In the state of power off, provide a high level pulse atleast for 100 Milliseconds to ON/OFF PIN to turn on the module by either toggling the push button switch or by cycling the GPIO through Low-High cycle.

The default state of ON/OFF GPIO should be low.

cd /sys/class/gpio
echo 45 > export
cd gpio45
echo “low” > direction
cd /sys/class/gpio/gpio45
echo "high" > direction
sleep 0.1
echo "low" > direction

Check that modem is visible on the USB bus by :

root@Yantrr:~# lsusb 
Bus 001 Device 004: ID 0930:6545 Toshiba Corp. Kingston DataTraveler 102 Flash Drive / HEMA Flash Drive 2 GB / PNY Attache 4GB Stick
Bus 001 Device 003: ID 05c6:9003 Qualcomm, Inc.
Bus 001 Device 002: ID 0424:2412 Standard Microsystems Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

In Yantrr Pre-Compiled VAYU2 Boot Image, for ease of user these regular commands with the GPIOs have been created as functions : pinexp, setout, setin, pinread.

pinexp 45
pinexp 60
setout 45 low
setout 60 high

Power off

In the state of Power On, provide atleast a 600 Milliseconds low level pulse to ON/OFF PIN to turn off the module.

cd /sys/class/gpio/gpio45
echo "high" > direction
sleep 0.6
echo "low" > direction

Soft Reset

To soft reset the modem, cycle the Modem On/Off pin through a Power-Off and then Power-On cycle. i.e.

  1. Power Off the Modem.
  2. Wait for 1-2s atleast.
  3. Power on the modem.

Hard Reset

There might arise situations where modem does not seem to be responding to any commands issued on AT commands port or it cannot be turned on/off. In such scenarios, issue hard reset to the modem. It can be done by either toggling Switch S2 for atleast 100ms or pulling GPIO60 low for 1s and then setting it high again.

cd /sys/class/gpio/
cd gpio60
echo "low" > direction
sleep 0.1
echo "high" > direction

Please use hard reset conservatively. Soft reset should be preferred under most conditions.

PPP connection using wvdial

Download and install Wvdial

apt-get install wvdial

Open the wvdial.conf file

$ nano /etc/wvdial.conf

Assuming that you have the USERNAME, PASSWORD and APN available for the service provider of the sim card being used, edit and make wvdial.conf file like this. Sample wvdial.conf file for AT&T and T-Mobile USA

[Dialer Defaults]
Modem Type = Analog
ModemPhone = *99#
ISDN = 0
Baud = 115200
Username = USERNAME
Password = PASSWORD
Modem = /dev/ttyUSB3
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Init3 = at+cgdcont=1,"ip","APN"
Stupid Mode = 1

Usually for GSM Networks, Modemphone is *99# or *99***1#. Consult your network provider for exact details in case you are facing difficulties. After editing, save and exit, now run wvdial for establishing communication.

$ wvdial

If all parameters are correct and everything is working, you should see a success message from wvdial. Once PPP connection has been established, you will see a ppp0 IP.

To check the status of wvdial and find out its IP open a new shell and use either of following:

  • Run ifconfig and find ppp0 in the list of network connections.
$ ifconfig
$ ifconfig ppp0
  • Check the network statistics for IP and their gateways and check the Iface column for ppp0
$ netstat -arn
* Kernel IP routing table 

Destination Gateway Genmask Flags MSS Window irtt Iface UG 0 0 0 eth0 U 0 0 0 eth0 U 0 0 0 usb0 UH 0 0 0 ppp0
  • Read the system messages as
$ cat /var/log/messages

It lists all the attempts at establishing ppp communication using the modem and IPs for the successful attempt.

Now all that is left is to route the network traffic over the gateway of ppp0 instead of eth0 so that GPRS communication is fully completed.


UC20/EC25 GNSS engine allows calculating location without any assistance from the network.

Please note that the /dev/ttyUSB1 is only GPS NMEA message output port

  • Turn ON GNSS

Note : By default GNSS engine is in OFF state on Modem Power Up.

  • Turn OFF GNSS
  • Positioning Information

For more AT commands refer device specific manuals from below section.

AT Commands Manual

All the AT commands can be executed on the serial port /dev/ttyUSB2 with baud rate of 115200 8N1.

Software Setup Guide

For use of VAYU2 with Beaglebone Black, we recommend to use pre-compiled Debian Yantrr Image. The pre-compiled Debian Yantrr Image has all the settings pre-configured for use of its various features such as 3G/4G modem, GPS, USB Host Port, 2 RS-232 Ports,etc.

Following instructions are only for Users compiling Beaglebone Black's Debian Image from scratch for VAYU2 use.

For compiling Beaglebone Black Debian Image from scratch follow Robert C Nelson BBB Wiki and add needed patches, install Quectel's WCDMA/LTE Linux USB Drivers while compiling.

Detailed compilation steps updating soon.

Also in the Debian Yantrr Image, for configuring various modules of cape at every boot up a script is executed. Its content is

root@Yantrr:~# cat
#!/bin/sh -e
/bin/sleep 10
/bin/echo ==============================
/bin/echo 'Setting pins'
/root/bin/pinexp 45			# Modem ON/OFF Pin
/root/bin/pinexp 60			# Modem RESET Pin
/root/bin/pinexp 50			# Ext-GPS Module RESET Pin
/root/bin/setout 50 high
/root/bin/setout 60 high
#For Quectel Modems
/root/bin/setout 45 low
/bin/sleep 4
/root/bin/setout 45 high		# Modem Power ON Sequence
/bin/sleep 0.1				#
/root/bin/setout 45 low			#
cd /lib/firmware
/bin/echo BB-UART4 > /sys/devices/platform/bone_capemgr/slots		# For Ext-GPS Module's Serial Port
/bin/echo BB-UART1 > /sys/devices/platform/bone_capemgr/slots		# For VAYU2's RS-232 Serial Port 1
/bin/echo BB-UART2 > /sys/devices/platform/bone_capemgr/slots		# For VAYU2's RS-232 Serial Port 2
#/bin/stty -F /dev/ttyO4 19200 raw					# Setting Ext-GPS Module's UART in raw mode
#ln -s /dev/ttyO4 /dev/gps1
#ln -s /dev/pps1 /dev/gpspps1
/bin/echo 'Done with pins and devices'
/sbin/ip route list exact default
/bin/echo 'All done'

With pre-compiled Debian Yantrr Image, no need of manual execution of above The script is configured to auto execute on board boot up using cronjob entry.