Here's something I ran into when I was connecting my 5.7e. We had pulled a Cat-5e run to the location when the house was built. When I received my 5.7e, I bought a power brick, a Trendnet TPE-101i, to supply the Power over Ethernet. I tested it in the utility room with the power brick connected directly to the 5.7e and the router using patch cords. Everything was hunky dory there. Then I went about setting it up in the operational configuration, with the touchscreen in its proper location, and the power brick at the other end of the Cat5 run in the utility room, between it and the router.
When I wired up the Cat5 at the location where the 5.7e was going to do, I did it the conventional way: I wired pins 1, 2, 3, & 6 on the RJ45s at each end, and I left the other four pins un-wired. I had assumed that the power brick would supply, and the 5.7e would receive, the power using the "Mode A" of the 802.3af standard -- that is, phantom power riding on the data conductors.
Well, that didn't work. The power brick in the utility room never recognized that the touchscreen was connected, so it never applied power. I took a close look at the 101i's manual, and it doesn't say which 802.3af modes it supports. I then looked at the 802.3af standard. According to the standard, if I'm reading it right, all devices that receive PoE must be capable of receiving power via either Mode A or Mode B. However, it is permitted for a PoE device to support only one or the other. So I thought: what if this brick only supports Mode B? That mode uses the two extra pairs in the Cat5 to supply the power, instead of phantom powering via the data lines.
So I went back and re-did my circuit, and wired all eight pins on the RJ45s per the standard. Then I plugged up the touchscreen, and connected the power brick at the other end. Viola: it worked! The power brick saw the touchscreen, and the touchscreen received power and booted up. However, that's rather annoying because if I ever want to use the other two pairs on the Cat5 for something, I can't.
So now I'm wondering. The reviews I read of the TPE-101i on Amazon didn't say anything about it only supporting Mode B. Nor does Trendnet's documentation say that, although it doesn't say that it supports both modes either. However, I thought it was pretty standard in the PoE market for power devices to support both modes.
So I need to confirm: does the 5.7e support both PoE modes? Because if it does, then I'm going to write a review on Amazon saying that the power brick only supports mode B, and purchasers need to be aware of that.
When I wired up the Cat5 at the location where the 5.7e was going to do, I did it the conventional way: I wired pins 1, 2, 3, & 6 on the RJ45s at each end, and I left the other four pins un-wired. I had assumed that the power brick would supply, and the 5.7e would receive, the power using the "Mode A" of the 802.3af standard -- that is, phantom power riding on the data conductors.
Well, that didn't work. The power brick in the utility room never recognized that the touchscreen was connected, so it never applied power. I took a close look at the 101i's manual, and it doesn't say which 802.3af modes it supports. I then looked at the 802.3af standard. According to the standard, if I'm reading it right, all devices that receive PoE must be capable of receiving power via either Mode A or Mode B. However, it is permitted for a PoE device to support only one or the other. So I thought: what if this brick only supports Mode B? That mode uses the two extra pairs in the Cat5 to supply the power, instead of phantom powering via the data lines.
So I went back and re-did my circuit, and wired all eight pins on the RJ45s per the standard. Then I plugged up the touchscreen, and connected the power brick at the other end. Viola: it worked! The power brick saw the touchscreen, and the touchscreen received power and booted up. However, that's rather annoying because if I ever want to use the other two pairs on the Cat5 for something, I can't.
So now I'm wondering. The reviews I read of the TPE-101i on Amazon didn't say anything about it only supporting Mode B. Nor does Trendnet's documentation say that, although it doesn't say that it supports both modes either. However, I thought it was pretty standard in the PoE market for power devices to support both modes.
So I need to confirm: does the 5.7e support both PoE modes? Because if it does, then I'm going to write a review on Amazon saying that the power brick only supports mode B, and purchasers need to be aware of that.
