This interface is designed to obtain its operating voltage from the remote batteries themselves, eliminating the need for an external power supply or power switch. It works with either 3 volt or 6 volt remotes without needing a selector switch. Construction is easy enough that nearly anyone can build one.

You will need less than a foot of small gauge insulated wire for the jumpers on the PCB, the smaller the better. This can be anything from #30 gauge wire-wrap wire to stranded hookup wire (#22 gauge or smaller). Solid insulated wire is a little easier to work with for making jumpers.

The easiest way to obtain a cable for the parallel port is to find (or buy) a preassembled computer cable having a DB25 male connector on one end with wires attached to pins 2, 3, 4, 11, and at least one of pins 18 through 25. Wires to other pins won't help or hurt. Do not exceed 10 feet in length. Cut off the other end and strip back the jacket about 2 inches. Cut off all unused wires flush with the jacket. Strip the remaining wires about 1/8 inch for soldering to the PCB.

You will have to scrounge for a female connector that will mate with JP1 in the remote. Talk to the other members of the group about sources. Chances are you will have to take a connector having ten or more pins and cut it down to size. Unless you have a jeweler's saw, this is a job for the Dremel tool. For a cable to this connector you can use any available 6-conductor jacketed cable (doesn't need to be shielded), a ribbon cable, or even five separate wires tied together in a bundle. Do not exceed four feet in length, and be sure to use stranded, not solid, wire.

First, make the PCB fit into the box. The hard way is to cut away the eight little ribs inside the box with a sharp knife or Dremel tool. A cleaner, safer, and easier way is to sand off about 1/32 inch along the top and bottom sides of the PCB. Lay a piece of coarse sandpaper face-up on a table top and run the board back and forth edgewise. It takes only a couple of minutes. While at it, sand off the rough notches where the dual board was broken apart.

Unfortunately the four mounting holes in the PCB do not match up with those inside the box. However, it is not necessary to screw the board down. It can just be allowed to float within the box. Be very careful if you try to drill new mounting holes in the board because the drill can easily drift over into the existing hole, and the phenolic material breaks easily. That's when you'll be glad the Radio Shack part is actually two boards in one. Elongating the existing holes with a small needle file works better.

Circuit boards are often coated with a thin layer of laquer to prevent the copper from oxidizing. Soldering will be easier and look neater if you clean the clad side of the board with a little household abrasive powder, followed by soap and water.

Using a fine tip marker pen or a pencil, label the peripheral holes 1 through 14 and A through F as shown in the illustrations, on both sides of the board. On the component side only, touch the end of the marker lightly to each of the eight resistor mounting holes, to identify them later when routing the jumpers.

Solder the IC socket in place. Note the non-symmetrical orientation of the board pattern and the exact position and preferred orientation of the socket, with the notched end toward pins 1 and 14.

Solder the seven jumper wires in accordance with the JUMPER LIST in the illustration. You can route these wires in any way that looks neat. Keep them as short and close to the board as you reasonably can, but don't let them pass over any of the eight marked resistor holes (so you won't melt any insulation when soldering the resistors later).

Bend the leads of all four resistors pretty close to the body, so they will fit into holes 0.30 inches apart. You might want to solder R4 first to make sure it winds up in the right place, since its value (BROWN-BLACK-YELLOW color bands) is different from that of the other three (BROWN-BLACK-RED). The resistors can be snug against the board, or up in the air slightly, whatever works among the jumper wires. It's a good idea to double check after all resistors are in place to make sure none of their leads melted any jumper insulation while hot.

After making or buying your two cable assemblies, solder them to the PCB as shown. It's not necessary to run separate wires to JP1-1 and JP1-2. Use one wire and solder it to both pins at the connector. If you have a ribbon cable assembly with all six wires, solder both wires from pins 1 and 2 to the board at terminal 14. It's also not necessary to make ground connection to all the pins 18 through 25 at the DB25 connector. It's shown that way to illustrate your options. A single wire to any one of them is all you need.

To make the following tests you will need an ohmeter to check each circuit path listed in the table. When the correct resistance value is shown as "0" it means there's supposed to be a direct connection between those two points, and the ohmeter should read less than one ohm. For the 1K and 100K readings, any value within 10 percent is OK. Whenever you can, try to make each measurement from the actual contact inside the socket or connector, so that the solder joints are included in the test. Use your own judgement on this. Connect the meter leads to small paper clips and use them as probes to TOUCH the IC socket and JP1 contacts. NEVER insert anything larger than the lead wire from one of your 1/4 watt resistors into an IC socket, or you may over-stress the tiny leaf spring so that it makes poor contact with the IC lead.

Place the board assembly temporarily into the box with the cables lying over the ends or sides you want them to exit, dress the cable wires so they have some slack, then mark both cables at the inside edge of the box. Remove the assembly and wind about ten layers of black plastic electrical tape around each cable so that the edge of the tape lines up with the mark. These "bumps" will act as strain reliefs to prevent pulling the cable out of the box when the lid is closed.

Cut or file a notch at the upper edge of each end of the box to fit whatever shape cable you have. Cut or file a corresponding notch in the rib that runs around the under side of the cover. Try to make the notches line up and fit the cables snugly, so that when the lid is fastened down it squeezes the cables. Put the PCB assembly back into the box, fasten the lid, and you're done.

Since the interface receives no power when unplugged from the remote, the REMOTEIF-check software cannot be used. If you followed the instructions under PREASSEMBLY TEST you will not need this test. After uploading or downloading data to a remote you don't have to unplug the interface to operate the remote unless you want to.

UEIC remote controls draw about 10 to 20 microamps of battery current during standby, and a brief pulse of about 10 to 20 milliamps when a button is pushed. The low standby current makes the batteries last almost as long as they would just sitting on a shelf. Preliminary tests show that when this interface is plugged into a remote the standby current increases to about 1/3 to 1/2 milliamp, and the power consumed while making an upload or download is about the same as for pressing a button. Even at this increased standby current the life of a AAA battery with the interface plugged into a remote is over 2,000 hours, and that of a AA is over 5,000 hours. That's why a power switch hasn't been included, and you don't need to worry about leaving the interface plugged into a remote all day long.

If that still bothers you and you want to add a power switch, don't connect JP1-1 to JP1-2 as shown. Instead, run two separate wires from pin 14 of the PCB, one directly to JP1-2, and the other to JP1-1 via the power switch, as shown in the alternate schematic. You can use either a miniature toggle switch, or a momentary pushbutton switch that you press for a few seconds when uploading or downloading. Other than lower cost, the advantage of the latter is that you can't forget and leave it on.

For those of you who have grown to love being able to disconnect your computer cable from the box, you'll have to innovate. Here are some ideas. There's probably enough room above the PCB assembly to simply wire a 26-pin header on five short (2 to 3 inch) wires, plug in the computer cable, and let the connector pair lie just above the PCB while the lid is fastened shut. This may dictate bringing a ribbon cable out of the side of the box rather than the end. Place a 1-1/2" x 2" sheet of thin plastic or cardboard between the connectors and PCB assembly to prevent any of the header's pins from shorting out to components on the board. Remember that if you have to remove the lid every time you disconnect the cable, the screw threads in the plastic box are not going to last very long.

Another approach is to make a rectangular cutout in the lid to clear the header pins, cement the header to the top of the lid, and use short wires to the board. Or just make the cutout fit a panel mount DB25 connector and use a DB25 to DB25 cable. Note that both metal and plastic lids are supplied with the box, so you can experiment twice.

There's also enough room to mount a modular phone jack on the lid, with short wires to the board. You might salvage a modular jack from an old wall plate or discarded telephone. Make sure it is a 6-wire jack and not the more common 4-wire type (RJ14). Look through the Radio Shack wall plates, adapters, plugs, and cable on pages 48 and 49 of their catalog. One suggestion: Build your modular-to-DB25 cable assembly first and make sure you are satisfied with it before you install the jack. It might be harder than you think.