Troubleshooting Reader Connectivity Issues


We encounter many requests for support around connectivity to our readers, gateways, and embedded applications (e.g. Speedway Connect).

The purpose of this article is to discuss techniques for troubleshooting and resolving communication connectivity issues with our readers and gateways. Each one of the troubleshooting steps mentioned are grouped into their appropriate section and can be done individually.

Table of Contents


Ways to Connect

There are two ways to connect to the Impinj readers and gateways:

  1. Connecting to the reader or gateway via the Ethernet port.
    1. Reader or gateway connected directly to a PC via Ethernet cable
    2. Reader or gateway connected to a network (e.g. via hub/switch)
  2. Connecting to the reader or gateway via the Console port.
    1. Reader or gateway connected directly to a PC via serial console cable (Here's how)
    2. NOTE: Use this connection to access the device's RShell command line interface; tag reads are not available via this connection

There are also configuration settings that need to be configured correctly for on-reader applications that need to work with outbound communications:

  1. Via DNS
  2. Via NTP

Connecting to the reader or gateway via the Ethernet port.

Basic Troubleshooting Steps

Troubleshooting Steps
1 Confirm the Ethernet cable is in the right port
  1. Take a look at the back of the reader or gateway and make sure the Ethernet cable is in the Ethernet port and NOT the Console port, which are both RJ45 connectors:
  2. An additional check is to note that the Ethernet port has LEDs, which should light up when a valid connection exists, while the console port does not.
2 Ping the reader/gateway
  1. Open a Command prompt.
  2. Ping the reader/gateway over the network via their hostname and ip address.
  3. Consider pinging both IPv4 and IPv6 addresses if on a dual IPv4/IPv6 network. E.g.
    1. ping -4 speedwayr-XX-XX-XX
    2. ping -6 speedwayr-XX-XX-XX

        Note: Please remember to replace the XX-XX-XX with the last three (3) HEX characters of the MAC address. (If the MAC address is 00:16:25:11:FA:E1 then the hostname will be speedwayr-11-FA-E1)

        Note: Please try adding ".local" or ".local.<tld>" to the end of the reader hostname if the pings do not work.

        Note: If the ping command does not initially succeed, flush the DNS cache per the directions further down this page.

        Note: We are under the assuming your network is configured with a router, DHCP and DNS server.

3 Telnet to the reader/gateway

There are multiple ways to accomplish this activity. One such way is PuTTY on Windows based systems or telnet commands on UNIX based ones.

1. In PuTTY your telnet command will be to your reader's hostname or IP address on port 5084 (the port used for LLRP communication on the reader) or 5085 (if encrypted). It will look like the example shown below:

or in a UNIX environment, you will issue the command:


2. After issuing that command, you should see a screen like the examples below. The first example is the response you will see from a Windows based system using PuTTY, while the second is from issuing the command from a UNIX based system. This shows that there is communication between the computer and reader port 5084.


4 Check DNS on the network
  1. In Windows Command prompt, issue:

> nslookup speedwayr-XX-XX-XX,

> nslookup <reader/gateway IP address>.

Both commands should resolve correctly to each other.

5 Connect when your PC Wifi is disabled.

The PC may be attempting to access the reader via its' wireless (WiFi) port instead of its' Ethernet port

1. Turn off PC's WiFi port, remove Ethernet cable and then re-insert allowing the “Acquiring Network Address” message (in lower, right-side Windows toolbar) to time out and then re-attempt

2. Once connection is established, you can re-enable WiFi

Note: Here is a link to a Microsoft article on how to change the network adapter priority to eliminate the need for turning off the Wi-Fi connection:

Cannot connect when directly connecting a single reader or gateway to the Host PC via Ethernet

Troubleshooting Steps
6 Re-install Bonjour
  1. Uninstall Bonjour from your machine
  2. Download Bonjour print services if not already done
  3. Install Bonjour print services on your PC
  4. Make sure Bonjour is installed on the PC via Control Panel > Add or Remove Programs.

Note: If you are unable to use Bonjour, please configure a host to have a 169.254.1.x ( mask) ip address and then access the reader via

7 Check .local name

Bonjour is used to access the reader/gateway by hostname when you are directly connected to it, but it may not help when the reader/gateway is on the network.

  1. Add .local to the end of the reader/gateway host name. For example, try pinging speedwayr-XX-XX-XX.local
  2. Note: Using .local depends on the tld assigned for your company. For instance, tld could be .local.tld, or something else.
  3. Note: We recommend that you register DNS names for the top-most internal and external DNS namespaces with an Internet registrar.
8 Check the default IP Address

The reader/gateway defaults to the following fixed IP address:

  1. Try connecting to
  2. Try to ping

Cannot connect when using Ethernet through a router, switch or hub:

Troubleshooting Steps
9 Use Wireshark to determine network issues
  1. Download and Install Wireshark from  
  2. Run wireshark,
  3. Select the appropriate network connections,
  4. Filter by "llrp"
  5. Watch the messages as you try to connect to the reader/gateway.  

The messages should give an indication of what is wrong with the connection.

Note: We are under the assuming your network is configured with a router, DHCP and DNS server.

10 Check the default IP Address

If your network does not support DHCP, the reader/gateway defaults to the following fixed IP address: If this

address is already in use, the reader/gateway will select a random fixed IP address in the link local

address range.

  1. Connect to
  2. If the prior step does not work, scan for other readers/gateways on
11 Flush the DNS cache on the PC


Cannot connect when using Windows Virtual Machine:

From time to time we get connectivity issue questions from customers using Windows Virtual Machines to run ItemTest.

Troubleshooting Steps

Verify the Windows Virtual Machine network settings are setup properly.


Try using different network settings until it works. Here is an example of how that might look in Virtual Box when selecting a Bridged Adapter:

It should be roughly the same in similar applications.



RShell related checks:

You may be able to access the reader or gateway either via ssh or console cable. If so, it is important to run thru the following RShell activities: 

Troubleshooting Steps
13 Ensure Dynamic (DHCP) mode set
  1. RShell (SSH or via serial/console cable) into the reader or gateway and issue these commands:
    1. show network summary
  2. If ipAddressMode does not equal ‘Dynamic’, issue the following RShell commands:
    1. config network ip dynamic
    2. reboot
  3. Check to see if the ip address is specified.
    1. The following would be a sign that the reader has not been assigned an IP address via DHCP, or assigned itself a link-local address (
    2. The following would be a sign that the reader did receive the ip address from dhcp

      Notice how an ipAddress is actually specified.
14 Setup the reader/gateway with a static IP address 1. Ensure IP address of reader/gateway is using same subnet mask as the PC
2. Check for duplicate IP addresses assigned on the same network. One way to do this is to turn off the reader/gateway and ping the ip address to see if another system is using it.
15 Check the logs

An explanation for how to acquire the reader/gateway logs can be found here:

  1. If you encounter an "Assert" error message in the logs this most likely means one of the reader/gateway programs has crashed and could be the reason the port is not open.
    1. Here is an example message from the logs that may occur:

Event9='May  9 14:07:10 (none) MC4: Layer1: Assert - File: /mnt/work/firmware/reader/apps/mc4/layer1/spaceman/rfmux_common.c, Function: RFMux_updateFirmware, Line: 1308'

2. These type of issues would require you to send the logs to so they so they can determine what is going on and check whether your reader/gateway is still under warranty.

16 Check port configuration settings

1. Run the following RShell commands to see if the configurable ports are enabled:

show network telnet

show network ssh

show network http

show network ftp

show network sftp

2. Now that you know what is enabled or disabled, configure the system for what you need using the following commands:

config network telnet enable

config network ssh enable

config network http enable

config network ftp enable

config network sftp enable


Note: Telnet is being removed as of Octane Firmware version 5.12


Cannot connect when using either Ethernet setup:

Troubleshooting Steps
17 Check whether the reader/gateway ports are responding.

There are multiple ways to accomplish this activity. One such way is Putty on Windows based systems (Shown below) or ssh commands on UNIX based ones.

  1. Download and install PuTTY from
  2. Run putty, enter the reader/gateway address.
  3. Try connecting with putty to port 5084 and 5085 and send us the output?  It should look like:

A working system would output something similar to:

18 Perform a factory reset on the reader/gateway
19 Try connecting via POE
  1. If you are currently powering the reader/gateway via a power adapter to the wall and have the capability to power the reader/gateway over POE, then try switching the reader/gateway to POE.
20 Try connecting via Wall Outlet
  1. If you are currently powering the reader/gateway via a POE and have the ability to connect with non-POE, then try switching the reader/gateway to wall outlet power via a Impinj power adapter.
21 Change Switch/Router Ports
  1. Have appropriate IT personnel move the current port on the switch/router the reader/gateway is connected to a different one.
22 Disable PoE on the Switch

The reader/gateway specification dictates that when both the power adapter and Ethernet cable with PoE are connected to the reader, the reader then uses the power adapter to draw power and uses the Ethernet for network communication.

We've received reports in the past where if customers were using a certain type of Cisco switch and the network communication did not work.

The Cisco switches have a behavior of disabling port operation if the PoE device doesn’t draw any current. The following Cisco support page explains the details of configuring PoE :

  1. When the reader/gateway is plugged into both power (wall.. aka brick) and PoE port, then disable PoE on the switch/router.
    1. One possible way to do this is:

(In this example slot 5, port 2 is being set to PoE = “never”.)

Switch# configure terminal 
Switch(config)# interface fastethernet 5/2

Switch(config-if)# power inline never

Switch(config-if)# end

23 Confirm power capabilities of PoE switch
  1. Confirm that you are not exceeding the power capabilities of the PoE switch.
    1. The Speedway Revolution draws 11.5W max so be sure that the switch supports the number of connected readers and any other powered devices. 
      1. Note: If the power level is too low, the reader will begin rebooting if not powering down.
    2. The xArray has been measured to draw 13.6W
      1. Note: If the power level is too low, the gateway can become highly erratic without rebooting or show the red fault LED remaining lit perpetually.

Note: All of our readers and gateways are compliant with the PoE 802.3af standard maximums of 15.4 watts. All PoE ports should be configured to support the maximum current draw.

Note: Most PoE switches will have a maximum power budget that can be exceeded if there are too many PoE devices connected.

24 Check the PoE cable length
  1. Confirm that the Ethernet cable run from PoE source to reader does not exceed 100m (~330 feet). 
25 Swap readers/gateways
  1. Swap known good readers/gateways with the one(s) that might not be working.
26 Swap Ethernet cables
  1. Swap known good cables with the one(s) that might not be working. This will identify any Defective Ethernet (RJ45) cable(s).


Cannot connect when another Ethernet connection already exists

Troubleshooting Steps
27 Uninstall existing on reader/gateway applications.

Visit http://<reader/gateway name or ip address>/

  1. Check to see if the LLRP Status is Disconnected or not.

2. Check "Application SW Version" in the "Details" section.

  • Note: If "Application SW Version" is missing, then Speedway Connect (or any other application) is uninstalled.

3. Now that you know whether something is connected or not and whether an on-reader application is running, you can uninstall the app by issuing the following RShell command:

config image removecap

28 Disable Speedway Connect

An alternative to uninstalling the cap, it may be you have Speedway Connect installed and running so it will be necessary to disable it. Speedway Connect will consume the 5084 LLRP port if enabled.  You can disable Speedway Connect by:

    1. Visit http://<reader/gateway name or ip address>/ and

    2. Visit https://<reader/gateway name or ip address>/

    3. Click the Green Tags Status button to Red Tags Status and click the "Apply" button:

29 Check for other applications connected to this reader/gateway

It may be other systems are currently connecting to the reader/gateway. Find them and get them terminated.

Rebooting the reader/gateway may also be an option.


"Connection Denied" Errors:

Troubleshooting Steps
30 Update the firewall rules

If a firewall is between your host and reader/gateway, it is highly likely the communication is being prevented from there.

  1. Add the reader/gateway IP address and/or host name to your firewall program as “safe” or “allowed”.
    • Alternatively, add the ports for communication to the firewall:





      FTP Port (If Enabled)

      To Reader


      SSH (RShell) Port

      To Reader


      Telnet Rshell Port (If Enabled)

      To Reader


      Speedway Reader Web UI

      To Reader


      Reader NTP Protocol

      From Reader
      162* UDP Port for SNMP Trap From Reader


      Speedway Connect UI (If installed)

      To Reader

      5084  *

      Unsecurred LLRP Port

      To Reader

      5085  *

      Encrypted LLRP Port

      To Reader

      These can be enabled and disabled
      * These ports are changeable
      ** Telnet is being removed from the reader with Octane FW version 5.10.2

31 Ensure you have the latest and appropriate region firmware installed.

Visit http://<reader/gateway name or ip address>/

  1. Check to make sure you have the latest installed ( as of 6/13/2017):

     2. Check to make sure the Regulatory Region is correct:

Connecting to the reader or gateway via the Console port.

Basic Troubleshooting Steps

Troubleshooting Steps
32 Confirm the Console cable is in the right port Take a look at the back of the reader or gateway and make sure the Console cable is in the Console port and NOT the Ethernet port, which are both RJ45 connectors:
33 Check modem settings are correct
  1. Expect the following settings to be used:

• Bits per second = 115200
• Data bits = 8
• Parity = None
• Stop Bits = 1
• Flow Control = None

34 Try Different Cables
  1. Use DB9-to-RJ45 (or DE9-to-RJ45) cable from Impinj (part # IPJ-A4000-000) or,
  2. If using different cable, ensure pin out matches the ones defined in section 2.8 of the Impinj Reader Gateway Embedded Developers Guide:
35 Ensure Adapter using FTDI chip

If using a USB-Serial adapter,

  1. Ensure the adapter is using an FTDI chip:

Note: There are some integrated cables now available that have the USB to serial converter built-in, E.G.:


Communication issues from the reader to the outside:

You may be able to access the reader or gateway either via ssh or console cable. If so, it is important to run thru the following RShell activities: 

Troubleshooting Steps

Make sure dns is setup properly


When switching to Static IP it has been brought up that on-reader applications cannot reach remote systems.

  1. Make sure your dns settings are correct.

    show network dns

  2. If not, add (and/or remove) the dns servers.

    config network dns add <ip of dns server>
    config network dns del <ip of dns server>

  3. reboot
  4. Another check is to see if the on-reader application can connect to the remote systems via IP Address.
37 Make sure ntp is setup properly

For NTP, it is important to understand that the time does not change immediately, and the rate of change is influenced by how big the time difference is between the current reader time and the timestamp provided by your NTP server; the bigger the difference, the more gradual the change. This is to limit any errors that might occur in the system by a rapid time change (log file timestamps, for example).

  1. Make sure your ntp settings are correct.

show system summary

show network ntp

a. Note: If the NTP Reach metric (NtpServerStatic1Reach) is zero then the reader has been unable to reach an NTP server at the IP address you have specified.

2. if not, add (and/or remove) the ntp servers.

config network ntp disable

config network ntp add <ip of ntp server>

config network ntp del <ip of ntp server>

config network ntp enable

3. reboot

38 Update your application to use instead of “localhost”

Octane firmware versions prior to 5.12 cause our readers to resolve hostname “localhost” via dns instead of the /etc/hosts file.  If someone or something adds “localhost” to the dns server that points to a machine on the network then all attempts to connect to the reader via llrp port 5084 will fail to work.

The workaround for this is to update your embedded application to connect via IP address instead of localhost.


Some less frequent issues:

1) Routing table issue
2) ARP cache is corrupt
3) Most modern PCs have an auto-crossover network card so that you can connect directly between your PC and the reader/gateway. However, if using an older PC or have tried everything else, you should try either connecting through a switch, hub or router or else use an Ethernet cross-over cable.
4) DNS server cache not updated issue. 

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