In this gallery, we will be taking a look at the HP JetDirect EX Plus Print Server (HP Part Number J2591A). Back in the 90’s, before HP started putting network cards in their printers, they sold these devices to translate a network signal in to a then-standard LPT printer port. Although I don’t know exactly when it was purchased, I can assume this particular device was created in the mid to late 90’s, as we will see proof of later. This print server accepted both BNC “Thin-Net” connections as well as the then-emerging 10Base-T Ethernet network standard.\n
\nCracking Open Tools Required:\n
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All device connections are on the back panel. This provided a neater look if this device was located on a table or shelf. Left to right, we have a BNC “Thin-net” 10Base-2 “Barrel” connection, a RJ-45 10Base-T Ethernet connection, a DB-25 Parallel LPT connection, and a standard DC power connection.\n
\nAlso on the back of the unit is the HP Model Number and Description.
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The bottom panel has some etched writing detailing FCC compliance as well as input power requirements. There are two screws that appear to be holding the device together. There are also two stickers providing device-specific information. Let’s take a closer look at those stickers.
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The left sticker contains a Serial Number as well as an AD number and a TR number.\n
\nAD: 0060B0251D6A
\nTR: 00060DA4B856\n
\nI can find no information on what these numbers mean.
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This appears to be a model information sticker. Across the top is “HP JetDirect Ex Plus Print Ser” and below the barcode is HNETHPEPS. It appears that the latter is some sort of model code. There is also a PO# (8781) which is probably HP’s purchase order number for this batch of devices.
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Removing the two Torx T-8 screws from a couple of photos back allows the back cover to be lifted out. Etched into the back cover is some text; the next screen shows that text up close.
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The text reads:
\nHP P/N 5002-2633
\nCODE H1306
\nGE CYCOLOY C2800
\n>PC+ABS-FR<\n
\nThis appears to be part information specifically for the back cover. Also stamped onto the back cover is a month and year of manufacture. The back cover reads 10-96.
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Removing the back cover also revealed the circuit board. Other than 1-2 larger chips and 2 stickers, there are dozens of resistors and capacitors. Close-ups of the chips and stickers follow.
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The left sticker reads:
\nJ2591-60002 MADE IN SINGAPORE A-3636
\nNELSGXT96376\n
\nThese appear to be more part numbers, this time for the circuit board and/or its contents. A Google search for the first number yields several results on purchasing these parts. However, I can find nothing on the latter two numbers.
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The right sticker on the circuit board contains the exact same numbers that were on the back outer panel with the Serial Number. Still no specific reference as to what these mean.
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Here is a close-up of the chips on the back side of the circuit board. The larger, black chip reads:
\nLH28F800SUT-70
\nSharp
\nJapan
\n9621.1 OD\n
\nThis chip is 8M of Flash Memory, probably used to store semi-permanent settings, such as IP configuration.\n
\nThe other, yellow chip reads:
\nSOMC 1601
\n472G
\nDALE 9616\n
\nThe information I found leans towards a high-capacity, high-resistance resistor.
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The circuit board simply lifts off its two large support pegs. Ahh, the days of simple construction. Inside the front plate is some more stamped text. The next screen is a close-up.
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The text reads:
\nHP P/N 5002-2634
\nCODE H1306
\nGE CYCOLOY C2800
\n>PC+ABS-FR<\n
\nObviously another part number and other information regarding the manufacture of this piece of plastic, these number only contain one difference from the numbers on the back plate. The first line on the back plate was HP P/N 5002-2633. Also stamped here is another manufacture date of 09-96. These two dates are the only information I have that this device was made in the mid-to-late 90’s, however I know that it was being used prior to the summer of 2000.
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Here we have the very busy front of the circuit board. Along the top edge are the connectors that peek out through the back. There are also two LEDs near the bottom right that provide status and activity signals to the top surface of the box. Also, between the LEDs is a third LED switch that provides the Test button functionality. The next several slides provide a closer view of many of the chips located on this side of the circuit board.
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The large chip almost dead center on the board is a SYMBIOS LOGIC chip. The numbers read:
\n1821-2188
\n0392322
\nDP00641 N9626\n
\nOther than this obviously being the BIOS chip for the print server, I can find no additional information.
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This picture shows the four larger chips to the right of the BIOS chip. The first, the “Level One” chip, is an Ethernet Repeater. The text reads:
\n9624 EJK8
\nLXT901PC
\n14939\n
\nTo the right of the large chip is a Fil-Mag chip marked “23Z91SM” and “9637”. This chip is an Isolation Transformer for AUI Transformers. If I remember my networking correctly, AUI was the connection type for Thick-net (10Base-5) networks. Although this device does not have an AUI connection, perhaps the chip is also used in Thin-net networks as well.\n
\nOn the far right is a SEEQ chip. The markings are “NQ83C92A” and “9625”. This chip is an Ethernet Transceiver for Thin-net and Thick-net networks. Apparently it works in tandem with the previous chip to provide the 10Base-2 network interface.\n
\nFinally, the chip directly above the larger chip is a VALOR chip, marked as ST7010. An Ethernet Transformer for 10Base-T networks, this chip must work in tandem with the larger chip to provide the network communications on that medium.\n
\nIt appears that these chips, or chips just like them, are found in most Ethernet networking products at least since Thick-net Ethernet was popular.
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Below the chips in the previous slide, but still to the right of the BIOS chip is a Motorola chip with the following markings:
\nMC68EC000FN10
\n0G74K
\nCPQMJ9635\n
\nThis chip is the microprocessor for the device. It is a low power 32-bit processor able to address 16 megabytes of memory.
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The chips in this picture are Siemens DRAM chips created in Germany, part number HYB514256BJ-70. These appear to be 1 megabyte chips organized into 256k 4-bit words with a 70 nanosecond access time and a 130 nanosecond cycle time. These chips almost certainly provide the print buffer.\n
\nAlso depicted here is a smaller Texas Instruments chip marked:
\n7705AC
\n69T
\nA6KV\n
\nThis appears to be a voltage controller for the RAM chips with a Programmable Time Delay feature.
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This picture, taken upside-down from the main circuit board picture a few photos back shows several chips. At the top-center is a Texas Instruments chip marked “67D1N6T” and “TL594C”. This chip is a Pulse-Width-Modulation Controller.\n
\nDirectly to the right of that chip is another chip marked:
\nF9Z24S
\nIR618J
\n10 90\n
\nThis is a Transistor from Vishay Siliconix. I imagine this has some relationship to the previous chip, but I’m not sure what, specifically, they do for the Print Server in general. Their proximity to the power connector and the LPT port might suggest relevance to either of those, however.\n
\nFinally on this image, in the lower left corner, is what appears to be a relay marked 400KD6J. I can find no information on this, however due to its proximity to the LPT port, I would guess that it provides some functionality to that interface.
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This final large chip on the main board is standing nearly upright in the bottom left corner. From Delta Electronics, this is a DC to DC Converter made in Hong Kong. It provides 5V to 9V conversion for the Ethernet connection(s). The model number, DPS0502B, suggests that this generates an output current of 200 milliamps and operates at 70% efficiency.
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Here are all five parts (counting the screws each) of the HP JetDirect EX Plus Print Server. Due to the age of this device, I was surprised and pleased to be able to find so many datasheets and descriptions of the integrated circuit chips used in this device. Some of the datasheets were amusing to read, especially those touting the “new” Thick-net and Thin-net technologies. There were even snide remarks against Thin-net as being “CHEAPERNET”.
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