Anyone know how the Head/Rack communicates with the Remote?

  • Hey All,

    before anyone responds with "through an ethernet cable", let me explain:

    Is the communication between the Head/Rack and the remote IP based (layer 3), or some proprietary Layer 2 connection? If layer 3, that would mean that either the Head/Rack includes a DHCP/BOOTP server, or the Head/Rack and remote are hardcoded - ??

    I'm asking because I'm considering adding an access point to my rack and am wondering how to configure the communication (tablet to AP to Rack)

    Thx in advance - M.

  • I believe you don't need to worry about IP layers. If you want to add an AP to your rack, and you are planning to setup:
    Head/Rack-->AP --> Remote and AP--wifi-->Table, you'll need an additional PoE switch o use and AP with PoE ports.

    You will need to use the Remote cable and any other Cat5E Ethernet cable to connect the Remote and KP head to a PoE switch like this:

    TP-Link TL-SG1005P V2 or later | 5 Port Gigabit PoE Switch | 4 PoE+ Ports @65W https://a.co/d/cgA6w1J

    The PoE switch needs to be connected (wired) to your local wifi router (AP).

    This was covered in this thread:

    SDR2020
    August 29, 2022 at 2:42 AM

    hope that helps.

  • From my experience, the Kemper does not act as a DCHP server. It sends discovery packets at startup and will use an external server if found (e.g. your AP). If no server responds it falls back to the so-called "link-local" network range.

  • From my experience, the Kemper does not act as a DCHP server. It sends discovery packets at startup and will use an external server if found (e.g. your AP). If no server responds it falls back to the so-called "link-local" network range.

    You're referring to an APIPA address, right? That makes sense.

    That also tells me my setup is not going to work. I got a TPLink PoE switch so I wouldn't have to use a PoE injector. Also got the PoE powered MicroTik maP, which has a super small footprint. Unfortunately, the maP only works in router or Bridge mode. In Bridge mode the DHCP server is disabled and in router mode the communication between the wireless and wired networks is NATed.

    On my Android tablet it looks like the app is using broadcasts to discover the Kemper, so that's not going to work across a router/NAT, and in bridge mode my tablet won't get an IP address, which means I'd have to enter an APIPA address manually every time. Also, the power brick for the TPLink is at least as big (if not bigger) as the switch.

    (listing all this info in case someone else is researching/trying the same thing).

    I saw your setup on the thread Syntek mentioned. What PoE injector is that? Looks like it has a pretty small footprint. And are the power supplies for the GL.iNet and the PoE injector the black and yellow bricks right above above the PoE?

  • You're referring to an APIPA address, right? That makes sense.

    That also tells me my setup is not going to work. I got a TPLink PoE switch so I wouldn't have to use a PoE injector. Also got the PoE powered MicroTik maP, which has a super small footprint. Unfortunately, the maP only works in router or Bridge mode. In Bridge mode the DHCP server is disabled and in router mode the communication between the wireless and wired networks is NATed.

    On my Android tablet it looks like the app is using broadcasts to discover the Kemper, so that's not going to work across a router/NAT, and in bridge mode my tablet won't get an IP address, which means I'd have to enter an APIPA address manually every time. Also, the power brick for the TPLink is at least as big (if not bigger) as the switch.

    (listing all this info in case someone else is researching/trying the same thing).

    I saw your setup on the thread Syntek mentioned. What PoE injector is that? Looks like it has a pretty small footprint. And are the power supplies for the GL.iNet and the PoE injector the black and yellow bricks right above above the PoE?

    Android behavior in the lack of a DHCP server is not very helpful. One would hope that its network stack would soft-fail back to APIPA but that's not the case. iOS devices behave properly in this regard. I was able to work around it by manually configuring my Android tablet to use an arbitrary address in the APIPA range. The Android is a backup for my regular iPad so I'm not 100% confident it will remember those settings in the real world - all I know for sure is that it did in my practice room.

    The POE injector in my photo is a TP-LINK TL-POE150S. The black "brick" is the injector's power supply. The GL.iNet was powered from a USB port built into the power strip. I use past tense for a reason. That port couldn't supply enough current to reliably run the router and I was plagued with random drops and disconnects. Since then I've switched to a POE enabled router as replacement for the injector and access point. This new setup connects to my iPad through a Lightning-to-ethernet adapter. With no DHCP server in the picture I quickly discovered the Android issue. Again, the iPad works just fine.

    I may take another shot at using the access point with its own power supply (in addition to the inject), but that will require a new power strip with at least (3) outlets. But, in fairness, I'm more likely to pickup a gently used Kemper Stage and retire the current rack to my cellar.