Recently we had a customer inquiry about the internals of one of our parallel port cards. To answer, we had to take a refresher course in what our design contained. That process led us to think: why not let interested technically-minded people see what’s inside the LAVA parallel EPP port design? We decided we would.
So here’s something never before seen outside of LAVA’s engineering department: the schematic design of our PCI-to-EPP parallel port bridge circuit. It’s the basis for LAVA’s Parallel-PCI. This design revolutionized PCI bus expansion in the industry, as it was the first implementation of a parallel port to take advantage of the speed of the PCI bus. Early versions of LAVA Parallel-PCI cards using this design wrote the circuit into a Xilinx FPGA (Field Programmable Gate Array); fairly soon afterwards it was incorporated into the first version of our LAVA ASIC, the application-specific integrated circuit that is the backbone engineering of LAVA PCI-bus serial and parallel cards to this day.
The design shown in this PDF is the newest production version of this design, and it’s what you get when you buy a Parallel-PCI, Parallel-PCI/LP, or Dual Parallel-PCI. It’s also the parallel port portion of the SP-PCI, or 2SP-PCI serial-parallel combo cards. All of these cards use this EPP parallel circuit.
The LAVA ASIC also contains circuits for serial ports, but that is a story for another day.
Sometimes it’s not rocket science.
Loblaw Companies Limited, a large food store chain based in Canada, needed a reliable method of adding serial ports to their POS systems. They were looking for a simple workhorse serial interface to connect the usual sorts of POS peripherals — weigh scales, printers, and bar code scanners — to systems that they had already spec’d into a deployment.
They chose RS-232 in preference to USB for these interfaces because above all they needed a robust and tamper-proof connection. Speed was not an issue: the key was keeping it simple. These POS systems would be operating about 18 hours a day, and downtime would be very costly.
So they went with LAVA’s Quattro-PCI/LP four-port card: the combination of domestic engineering and manufacturing, unlimited free technical support, and the LAVA Lifetime Warranty were all selling points. Moreover, they wanted a low-profile PCI card with a fanout-cable, but using a full-height bracket.
A crucial differentiator came on the smallest of customizations however: the systems Loblaw was using were just slightly incompatible where the peripherals and the serial connector physically mated: the small screws on the cables were just slightly too long for the peripherals. This extra length was critical however: the POS stations could not be deployed with cabling that was not securely fastened between the POS system and the peripheral.
LAVA’s solution was simple: in final assembly of product for Loblaw, a small spacer was added so the cable could be positively attached to the POS station. That’s all it took, and LAVA, as the manufacturing source, was able to readily implement this customization. Problem solved!
A little-known fact: DOS commands can be sent through LAVA Ether-Serial Links. And it’s actually simple to do. With an Ether-Serial Link configured in Windows Driver mode, and with its port activated as usual, all you need to do is pipe DOS data (using the conventional DOS redirection command “>”) to the serial port of the device server, which will send it to the target device. The diagram below shows this setup connecting a DOS application to a piece of factory equipment.
This concept is easy to test, as the diagram below shows. While a two-device setup is used to demonstrate this concept, only one Ether-Serial Link is needed to actually send data to a peripheral, as we saw above. In the diagram below, the DOS application on the left is sending data to the serial device server on the left, by piping its data to COM 4.
That Ether-Serial Link is connected to the serial port of the Ether-Serial Link on the right, which is in turn monitored by Hyperterminal. DOS commands piped to COM 4 are received at COM 5.
There is one limitation to this use of Ether-Serial Links to transmit DOS data: DOS will only allow this on COM ports 1 to 9.
The Detroit Institute of Arts (DIA) is a renowned art museum in the city of Detroit. In 2003, the DIA ranked as the second largest municipally owned museum in the United States, with an art collection valued at more than one billion dollars. It encloses over 100 galleries and now covers 658,000 square feet (61,130 m²); a major renovation and expansion project completed in 2007 added 58,000 sq. ft. (5,388 m²).
And even with that, not all its collections are currently on display. They are storing other materials off-site. When the DIA Operations people want to check and control the temperature in an off-site location they use a serial device server — the LAVA Ether-Serial Link (ESL) — in Windows Driver mode to access that information.
By using the LAVA’s ESL they have full access and control over climatological information from wherever they are.