Printers

Cracking Open the HP JetDirect EX Plus

By · March 16, 2009, 4:53 AM PST

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  • HP JetDirect EX Plus

    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.

    Cracking Open Tools Required:

    • Torx T-8 Screwdriver


    Photos by Wally Bahny for © TechRepublic

  • Back Panel

    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.

    Also on the back of the unit is the HP Model Number and Description.

    Photos by Wally Bahny for © TechRepublic

  • Bottom Panel

    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.

    Photos by Wally Bahny for © TechRepublic

  • Bottom Panel - Left Sticker

    The left sticker contains a Serial Number as well as an AD number and a TR number.

    AD: 0060B0251D6A
    TR: 00060DA4B856

    I can find no information on what these numbers mean.

    Photos by Wally Bahny for © TechRepublic

  • Bottom Panel - Right Sticker

    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.

    Photos by Wally Bahny for © TechRepublic

  • Bottom Panel - Inside

    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.

    Photos by Wally Bahny for © TechRepublic

  • Bottom Panel - Inside - Text

    The text reads:
    HP P/N 5002-2633
    CODE H1306
    GE CYCOLOY C2800
    >PC+ABS-FR
    This 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.

    Photos by Wally Bahny for © TechRepublic

  • Circuit Board - Back

    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.

    Photos by Wally Bahny for © TechRepublic

  • Circuit Board - Back - Left Sticker

    The left sticker reads:
    J2591-60002 MADE IN SINGAPORE A-3636
    NELSGXT96376

    These 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.

    Photos by Wally Bahny for © TechRepublic

  • Circuit Board - Back - Right Sticker

    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.

    Photos by Wally Bahny for © TechRepublic

  • Circuit Board - Back - Chips

    Here is a close-up of the chips on the back side of the circuit board. The larger, black chip reads:
    LH28F800SUT-70
    Sharp
    Japan
    9621.1 OD

    This chip is 8M of Flash Memory, probably used to store semi-permanent settings, such as IP configuration.

    The other, yellow chip reads:
    SOMC 1601
    472G
    DALE 9616

    The information I found leans towards a high-capacity, high-resistance resistor.

    Photos by Wally Bahny for © TechRepublic

  • Front Panel - Inside

    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.

    Photos by Wally Bahny for © TechRepublic

  • Front Panel - Inside - Text

    The text reads:
    HP P/N 5002-2634
    CODE H1306
    GE CYCOLOY C2800
    >PC+ABS-FR
    Obviously 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.

    Photos by Wally Bahny for © TechRepublic

  • Circuit Board - Front

    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.

    Photos by Wally Bahny for © TechRepublic

  • Circuit Board - Front - BIOS

    The large chip almost dead center on the board is a SYMBIOS LOGIC chip. The numbers read:
    1821-2188
    0392322
    DP00641 N9626

    Other than this obviously being the BIOS chip for the print server, I can find no additional information.

    Photos by Wally Bahny for © TechRepublic

  • Circuit Board - Front - Right Chips

    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:
    9624 EJK8
    LXT901PC
    14939

    To 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.

    On 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.

    Finally, 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.

    It appears that these chips, or chips just like them, are found in most Ethernet networking products at least since Thick-net Ethernet was popular.

    Photos by Wally Bahny for © TechRepublic

  • Circuit Board - Front - Processor

    Below the chips in the previous slide, but still to the right of the BIOS chip is a Motorola chip with the following markings:
    MC68EC000FN10
    0G74K
    CPQMJ9635

    This chip is the microprocessor for the device. It is a low power 32-bit processor able to address 16 megabytes of memory.

    Photos by Wally Bahny for © TechRepublic

  • Circuit Board - Front - RAM

    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.

    Also depicted here is a smaller Texas Instruments chip marked:
    7705AC
    69T
    A6KV

    This appears to be a voltage controller for the RAM chips with a Programmable Time Delay feature.

    Photos by Wally Bahny for © TechRepublic

  • Circuit Board - Front - Left

    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.

    Directly to the right of that chip is another chip marked:
    F9Z24S
    IR618J
    10 90

    This 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.

    Finally 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.

    Photos by Wally Bahny for © TechRepublic

  • Circuit Board - Front - Standing Chip

    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.

    Photos by Wally Bahny for © TechRepublic

  • Fully Cracked Open

    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".

    Photos by Wally Bahny for © TechRepublic

HP JetDirect EX Plus

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.

Cracking Open Tools Required:
  • Torx T-8 Screwdriver


Photos by Wally Bahny for © TechRepublic
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