Interesting to come across one of these in my junkbox. I remembered being amazed by one of these – many schools and small businesses used this decide to turn their parallel ported printers into network printers. I was amazed at the small size and the fact that it could run on the network. It still needed a power supply though – how else was it supposed to get its power? No PoE back then …
This is a flashback since parallel port printers are no longer the norm, and the manufacturer doesn’t support this item anymore. It features a 10Mbit/s Ethernet port, now considered antiquated. There’s no drivers available anymore, and no complete documentation I can find. I have tried giving it some power, the lights come on, but I can’t find it on the network, it doesn’t grab an address from DHCP – however, I have no parallel port printers to use with it either. I don’t even know which printers are supported. Its small size was a marvel of engineering – looking on the inside reveals just how much care they had to make it small.
First of all, this is the image from one side. What you can notice is that this device was constructed using a “sandwich” technique of two double-sided PCBs with an interconnection in-between. This top PCB has the centronics connector soldered to it, the interconnection header double-row, two SRAM chips from EliteMT and an unidentified U3. It has been cut very carefully to give space to the Ethernet jack which is as tall as the two stacked boards and the power barrel connector.
From the bottom side of the bottom PCB, it looks pretty bare. The Ethernet jack is soldered to it with a very low-profile magnetic transformer for the Ethernet port. Back then, these potted transformers used to be very tall and bulky, nowadays, they’re even integrated into the jack into a magjack.
And opening up the two boards and fanning them out, you can see what powers this whole contraption. An AMD Am188EM-40KC CPU (40Mhz, x86 compatible) powers the device. There is a crystal, two LEDs for status, an MX 512Kbyte Flash Chip (29F400TTC) which contains the program data. A Davicom DM9008F MAC is used to interface with the network with its own crystal, voltage regulator and polyfuse for protection.
I guess the design is something which only engineers can appreciate. This device is dated back to 2000 or thereabouts – so to me, this kind of design is quite impressive for the time. The density is so high, I can’t see much space for anything extra!