Communication between my tuner and computer does not work.

June 12, 2024

Tuner Setup

Symptoms / Solutions:

The user is trying to connect to the tuner:

– To calibrate the tuner
– To send commands via telnet
– To control tuner for a LP or Noise project

Possible reasons for failure include:

1. PC Configuration
2. Physical iTuner connection
3. FDCS communication issues
4. iTuner hardware issue

Before continuing to next sections, ensure that the tuner is powered by verifying that the display is on and is displaying the IP address. If the display does not show the IP address, skip to section 4.

As well, if you reset (power cycle) the tuner, the tuner should initialize horizontally and vertically. The LEDs for movement should come on and turn off when initialization is complete. If this does not happen, skip to section 4.

1. PC Configuration

This step may cause other network features to stop working depending on your LAN setup.  For more information see your network administrator.

iTuners are shipped from the factory with the following IP addresses:

– Load Tuner:
– Source Tuner:

These addresses should be displayed on the front display of the tuner. If the display is not powered, refer to section 4.

To control the tuners with these addresses, the PC needs to have a fixed IP address (with DHCP disabled). The tuner uses a subnet mask of Therefore the first to numbers of the PC IP address must match the first two numbers of the IP address of the iTuner. Therefore is a common choice of IP address for the client PC.

To change the IP address of the PC (in Windows 7):

a. Open the Windows Control Panel and choose Network and Internet (or Network Connections).

b. Select Network and Sharing Center.

c. Select Change adapter settings.

d. On the network adapter dedicated to iTuner communication, right-click and select Properties.

e. In the list of items, select Internet Protocol Version 4 (TCP/IPv4) and click Properties.

f. Select Use the following IP address. Enter a compatible IP address for the PC. The default subnet mask for the PC is and can be entered in the subnet mask field. Press OK.

2. Physical iTuner Connection

After verifying the computer settings, the following verification should be the physical tuner connection to the computer.

The simplest connection is a direct crossover cable connection between the tuner and the computer. Make this connection and telnet the tuner (Start -> telnet <IP address>). Telnet is not installed by  default on Windows 7. To activate the installation: Control Panel -> Programs and Features -> Turn Windows features on or off -> Telnet Client -> OK.

A command prompt window should appear with a similar output to the following:





This successful connection confirms that the tuner is functional and that it is capable of communication.

If the connection works with a direct cable connection, but does not work when connected through a router/switch, the router/switch may not be functional.

If this step is not successful, then possible problems areas are:

– The network cable is broken (or not crossover)
– The network card of the computer is not functional
– The network connector on the tuner is damaged (see section 4)
– The tuner is has an electronics issue (see section 4)

3. FDCS Communication

If all of the connections in section 2 are working, but the tuner does not work when used in FDCS, then the following steps should be verified

Check the tuner definition window in FDCS. The tuner definition should have the controller defined as TCPIP and the IP address as shown on tuner display.

The only other possible issue is with the VISA installation. The software uses the VISA standard to communicate with the tuner.  If VISA is not installed on the target PC, the packaged version of NI-VISA can be found on the installation DVD.  Do not install multiple versions of VISA on the same computer. If you suspect VISA as the possible cause, uninstall the current installation and reinstall it.

4. iTuner Hardware

There are only a few verifications that the customer can do to diagnose hardware issues of the tuner.

If there is nothing displayed on the display (seems unpowered), verify that the power adapter is plugged in and functional. The normal power adapter is 12V/5A.

If the display appears with darkened squares on the display, ensure that there is nothing attached to the serial connector on the tuner.

If the display shows an error message (such as ppmc error), there is an electronics issue with the tuner.

The power connection and network connection may become damaged or detached from the electronics due to improper handling. The user can attempt to determine this by moving the cable when attached to the connector and inspecting the connector.

The most likely outcome from an iTuner hardware issue is that it should be returned to the factory for repair. Contact Focus Microwaves at 514-684-4554 if you believe this to be the case.

Keywords: Setup, iTuner, telnet, communication failed

Last date modified:  February 2, 2017