pikvm

---
title: TESMART managed multiport KVM switch
description: How to control the TESMART managed switch with PiKVM to allow the switch to connect to multiple hosts
---

The TESMART managed switch can be controlled by PiKVM to allow it to
connect to multiple hosts. A typical scenario is a single PiKVM device
which can control and switch between multiple hosts or servers using the
TESMART switch. UI elements can be added to the [GPIO dropdown](gpio.md)
to allow switching between hosts from the PiKVM webpage.

The instructions here were tested with the [TESMART HKS1601A10 HDMI 16x1
switch](https://www.amazon.com/dp/B07D2ZMF5B ). This should work with
any of the other TESMART variants which have a LAN port - there is both
a 8x1 and 4x1 variant.  This was tested with an RPI4, but as this is
executed over a network protocol, this should with almost anything.


## Connections

From a high level, the TESMART switch uses standard connections to the host machines (USB-A to USB-B and HDMI). The Raspberry Pi OTG connector (the one coming from the USB-C port on a Pi 4 via the custom splitter cable or device) should be connected to one of the USB 2 output ports on the TESMART switch (not the keyboard/mouse port). Based on your specific devices, and to get boot images to mount, you may need to connect this through a USB 2 hub.

1. Connect the USB-A cable from the Raspberry Pi OTG port to one of the TESMART switch USB 2 output ports on the back of the switch (not the keyboard/mouse ports).

2. Connect the HDMI out from the TESMART switch to the Raspberry Pi CSI-2 to HMDI input.

3. Connect the LAN port on the front of the switch using standard ethernet cable into one of your network switches.

4. Connect host USB and HDMI cables from the TESMART switch to the machines to be managed per the switch instructions.

!!! warning
    There is a limitation in the underlying PiKVM software related to plugging video cables from a host which is already powered and connected to a monitor to a Raspberry Pi CSI2-HDMI encoder. These limitations apply equally when using the TESMART KVM switch. If video is not present in PiKVM, try keeping all host machines off and connecting them directly to the TESMART switch before powering the hosts on.


## Setting the IP Address of the TESMART switch

In some ways, this is the most complex part of this. The default IP address of the TESMART switch is 192.168.1.10. If that happens to work with your IP addressing scheme and current set of addresses, then you may be all set. This IP address is not configurable via DHCP or other standard mechanisms. The only way to change it is with a Windows utility available on the [TESMART Downloads Page](https://support.tesmart.com/hc/en-us/articles/10271501164953-LAN-RS232-Control-Software).

If you need to change it, you will first need to connect to the switch with a Windows machine, most easily directly through an ethernet cord, with your Windows laptop (or VM) up and assigned to a fixed IP address, such as 192.168.1.5. Once you've launched the utility you will see this screen:

<img src="tesmart_controller_1.png" alt="Configuration screen for TESMART Windows controller utility"/>

On this screen, ensure you are on the "General" tab. Click the radio button for "Network control". Change the IP address to the default for the switch (may already be this -- 192.168.1.10). Press the "Connect" button. Should make the status light go green, as well as the selected port.  If you do not get a connection here, you cannot proceed to change the IP address.  To change the IP address, change to the "Settings" tab at the top. You will then see this screen:

<img src="tesmart_controller_2.png" alt="Configuration screen for TESMART Windows controller utility"/>

On this screen, change to your desired IP address, gateway, mask, and port. Then press apply. Watch the box on the right to see if it applied OK. Press Query again to double-check. The actual IP address will not be changed until you power off/power on the switch. Make sure you have these settings correct, because if you get them wrong you would have to connect over RS232/serial and not the network.

There may be alternatives other than changing the IP address in this manner if you don't have access to a Windows machine or if this address doesn't work for you. See this [README](https://github.com/bbeaudoin/bash/blob/master/tesmart/README.md) for other options (Images and concepts from the bash file were borrowed for creation of this plugin).  This also contains a summary of the protocol, which is also available on the TESMART downloads page.


## Adding UI elements to control the KVM switch

The UI can be updated to add buttons to switch between KVM inputs and indicators for which input is currently selected. The instructions below will make these available in the PiKVM UI after clicking the "Switches" menu button in the KVM view.

1. Enable read-write mode on the SD card via `rw`

2. Edit the `/etc/kvmd/override.yaml` file and include the following:

    ```yaml
    kvmd:
        gpio:
            drivers:
                tes:
                    type: tesmart
                    host: 10.10.1.10
                    port: 5000
            scheme:
                server0_led:
                    driver: tes
                    pin: 0
                    mode: input
                server0_switch:
                    driver: tes
                    pin: 0
                    mode: output
                    switch: false    
                server1_led:
                    driver: tes
                    pin: 1
                    mode: input
                server1_switch:
                    driver: tes
                    pin: 1
                    mode: output
                    switch: false    
                server2_led:
                    driver: tes
                    pin: 2
                    mode: input
                server2_switch:
                    driver: tes
                    pin: 2
                    mode: output
                    switch: false    
                server3_led:
                    driver: tes
                    pin: 3
                    mode: input
                server3_switch:
                    driver: tes
                    pin: 3
                    mode: output
                    switch: false    
            view:
                table:
                    - ["TESMART Switch"]
                    - []
                    - ["#Server 1", server0_led, server0_switch|Switch]
                    - ["#Server 2", server1_led, server1_switch|Switch]
                    - ["#Server 3", server2_led, server2_switch|Switch]
                    - ["#Server 4", server3_led, server3_switch|Switch]
    ```

3. Return to read-only mode for the sd card via `ro`

4. Restart the `kvmd` service: `systemctl restart kvmd`


## Switching between hosts in the UI

To switch between hosts, enter the KVM UI and click the "Switches" menu. You should see your inputs, one of which will have a green circle indicating it is currently selected. Click the other inputs to change the selected host.