FD142 User Manual


FD142 Description

In most of the time, users need to reconnect the BRI/PRI line to a redundant server maintained by UPS when main PBX Server is power off. It may cause a little extra work for people who use simple and small PBX servers. But for those who run complex PBXs in server rooms, it becomes real problems.


How to eliminate this problem? The release of OpenVox FD142 failover box for BRI/PRI answers it. The FD142 can automatically switch the BRI/PRI line to the redundant server when the power of the main PBX server has been cut off and will automatically switch back to normal when the power is on again. In this way, no more worries about getting the BRI/PRI line connected to the redundant server when the main server is down.


FD142 is controlled through an Asterisk loadable module res_failover.so. This module keeps sending “running” signal to redundant server when Asterisk is running. Once Asterisk is down or system power is cut off, the module will not be able to send out the “running” signal to FB40/FD40 and thus FD142 will automatically switch to the redundant server.

FD142 provides a reliable and flexible solution to Asterisk PBX.

FD142 Features

l  FD142 contains 4 E1 / T1 / BRI ports and two Ethernet ports.

l  Easy installation; uses USB to connect computer or server. In order to provide more stable power supply, a USB interface for two connected hosts.

l  Industry standard USB type B connector.

l  USB 2.0 and 1.1 compliant.

l  FD142 supports all OpenVox D series and B series cards, Digium and other compatible digital cards.

l  Two indicator lights, red and green. Two lights, said an Asterisk work normal, FD142 work. Only when green light said Asterisk hangs, FD142 switch to the backup phone.

l  Supports multiple FD142 devices in one system. Support the BRI or PRI circuit connection.

l  Each network interface is divided into four mouth end, A, B, C, D, respectively, the interface of A and B are connected. Digital card.net client any end of the connection of A and B, redundant one interface can according to your needs, our TAP the card, to record, so as to meet your requirement for functional diversification. C and D connected to digital card of CPE, D is one end of the primary server, C is the standby server. For cable connection, LAN received any end of the A or B, D connected to the main network,C connect backup network.

FD142 Installation Guide

Hardware Connection



Device Driver Detection

The device driver of FD142 has been integrated with many Linux distributions. Users can run the following command to see if the FD142 has been recognized or detected by the system.

# dmesg | grep  FTDI




User can also run the lsusb command to check if the FD142 device is connected.

# lsusb

FD142 Working Instruction

As shown:

When the PBX Server is ON and Asterisk works, the signal goes from: 

1->LAN(red) 2->Main Network(green)

When the power of PBX cut off or Asterisk abnormal work, the signal goes form:

            1->LAN(red)  2->Redundant Network(purple)



FD142 Software Installation

Before installation, make sure the host system (LINUX) is running good, whether the DAHDI and Asterisk installation well, whether boards (Analog cards) drivers have loaded into the system. If you buy our cards, has not yet installed, you can go to our official website to download the user manual, then install. After everything installed, and then into the  following steps.

Software Download



Software Installation

1)Unzip the file


#tar  –xvzf  failover-1.0.1.tar.gz

#cd  failover


2)Copy the file to res directory under asterisk


# cp  res_failover.c  /usr/src/asterisk-**/res/


3)Copy the configuration file to /etc/asterisk directory


# cp  failover.conf  /etc/asterisk/


4)Compile and install


#cd  /usr/src/asterisk-**/


#make  install


5)Reboot asterisk


Explanation of Configuration Files



; Kick the soft watchdog every 4000ms

; default value: 4000

; Between 100ms and 9000ms




; default value: yes








  • [openvox_failover_1]:Name of FD142 Device, to distinguish from different devices, a must to configuration;
  • device=/dev/ttyUSB0:Name of USB device that FD142 uses, a must to configuration;
  • kick_time_interval:the time interval of software watch dog; the default time is 4000ms, user can customize the time with 100ms for Minimum and 9000ms for Maximum;
  • event_cmd:event command, the default is logger, it will record the FD142 status in system log;
  • autorun:this decides if FD142 will start when asterisk boots; the default is yes which means the FD142 starts when asterisk boots; if no, the FD142 will not start when asterisk boots and user may need manually boot the device by running failover start command.

Steps to Use

1)Start asterisk

   # asterisk  –vvvgc

2)Start FD142 device

      *CLI> failover start

3)Stop FD142 device

      *CLI> failover stop

4)Show FD142 device information

   *CLI> failover show

5)Reload FD142 device configuration file

   *CLI> failover stop    Before reload the configuration file, must stop all FD142 device

*CLI> failover reload   Reload the configuration file

6) Check the connection

     *CLI>pri show spans

7)Reboot DAHDI

         *CLI>dahdi restart

Technical Support

If you meet any technical problems when using OpenVox products, you can check our Forum for help or contact us directly be the following ways:


  1. BBS feedback problems

You can put your issued to our BBS encountered technical problems, we will in the shortest possible time solve the problem of you mentioned.


  1. Email Support

You can email your technical problems to the following emails:


Unless it is an emergency, this is always the most efficient way to get support.




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