DD-2902

BABOS SOFTWARE

How can you make a link cable between PC and CASIO

Complete DD-Link cable:

DD-Link cable's schematics

With 25 pin DSUB connector:

With 9 pin DSUB connector:

Parts list

BC547 transistor	2 pcs
BC557 transistor	1 pc
1N4148 diode	5 pcs
ZPD5.1 Zener diode	1 pc
10 KOhm 0.1W 2raster resistor	4 pcs
4.7 KOhm 0.1W 2raster resistor	1 pc
2.2 KOhm 0.1W 2raster resistor	1 pc
Silicon tube Ć1.5mm x 20mm	1 pc
Shrinkable tube Ć4.8/2.4 mm x 10mm	1 pc
LiYCY Cable 2x0.14	1.2...1.5 m
2.5mm Stereo Jack plug	1 pc
9 or 25 pin DSUB connector (female)	1 pc
9 or 25 pin DSUB connector cover	1 pc
DSUB or RG58 Strain Relief Boot	1 pc
Printed-circuit board	1 pc

You can download the files of Printed-circuit board if click to here,
and can fabricate the PCB film and the PCB by a PCB producer from these files (Aperture, Gerber, Drill program)
You can manage the PCB fabrication in the Internet:
You can find a local PCB producer in the Internet by google:
...and can send the downloaded and zipped PCB files for them by E-Mail as attachment.

Parts list with pictures:

BC547 transistor	2 pcs
BC557 transistor	1 pc
1N4148 diode	5 pcs
ZPD5.1 Zener diode	1 pc
10 KOhm 0.1W 2raster resistor	4 pcs
4.7 KOhm 0.1W 2raster resistor	1 pc
2.2 KOhm 0.1W 2raster resistor	1 pc
Silicon tube Ć1.5mm x 20mm	1 pc
Shrinkable tube Ć4.8/2.4mm x 10mm	1 pc
LiYCY Cable 2x0.14	1.2...1.5 m
2.5mm Stereo Jack plug	or	Special Jack cover and turned plug	1 pc
25 pin DSUB connector (female)	or	9 pin DSUB connector (female)	1 pc
25 pin DSUB connector cover	or	9 pin DSUB connector cover	1 pc
RG58 Strain Relief Boot	or	DSUB Strain Relief Boot	1 pc
Printed-circuit board	1 pc	PCB files download <= click here

You can download the files of Printed-circuit board if click to here, and can fabricate the PCB film and the PCB by a PCB producer from these files.

You can find these parts in the Internet by google:

Tools you will need

Soldering iron	-	it's useful to get a clamp thing if you can find one to act as a second pair of hands.

Test meter	-	to test all the connections. Also needed to work out which part of the 2.5mm stereo jack connects to which connector on the back of it. Multimeters can act as test meters.

Lighter	-	to warm of Shrinkable tube

Wire strippers	-	the hot wire strippers is better for thin wires

Pliers	-	cutting pliers and taper pliers and tweezers or flat pliers

A screw driver	-	watch-maker's or mechanician's screwdriver

Bench vice	-	Mechanician's bench vice to hold of the connector and plug during soldering.

Universal lathe with collets	-	it's useful to turn the Jack plug and cover if you can get at one in your work place.

Needle file	-	if you haven't got a Universal lathe.

Materials

Roller soldering tin	-	resinaceous, Ć0.8mm

Soldering fluid / oil	-	it's good help to soldering of cable

Instructions

There are two ends to the link - the calculator end and the computer end. You can make either end first it doesn't matter.

Calculator end

This is perhaps the most fiddly part of it. You have three options: either use a plug, a socket, or half your calc-to-calc lead.

DD-Link's special Jack plug:

The cover of special DD-Link Jack plug is thin, 7 mm diameter, that can be connected to the calculator, and the calculator don't titl up on plug. It can be turned from Poliamid bar by universal lathe in collet.
The connecting part of plug is special form, correspond with original CASIO^® connector, that can be connect to traditional CASIO^® SF-... manager calculators. It can be turned from commercial Jack plug by universal lathe in collet.
(The CASIO^® calculator socket is not standard 2.5mm Jack, that cannot connect the commercial Jack plug to CASIO calculators.)

But you can use a 2.5mm stereo socket instead of plug too: You then plug the calc-to-calc cable (original CASIO^® SB-62) into the socket and plug the other end into the calculator. This ensures a perfect connection and is a more robust solution than using a plug - plugging and unplugging can damage fragile soldering.

Your other option is to cut your calc-to-calc cable (original CASIO^® SB-62) in half to use the 2.5mm plug from one end. If you choose to do so, then you will find that the tip of the 2.5mm plug is the red wire, the middle ring on the plug is the white wire, and the other (copper) wire is the ring nearest the base (see diagram above). If you don't want to sacrifice your calc-to-calc cable, you could attach a readily-available 3.5mm socket to one cut half of the calc-to-calc cable and a 3.5mm plug to the other. Make sure both the socket and plug are stereo. Your calc-to-calc cable will still work (make sure you get the connections right - use a test meter) and you can use one half to connect to your computer link via another 3.5mm plug and socket.

Calculator end - Using a plug

If you use a plug then (depending on its design) you may need to carefully file away some of the metal from around its base to let it fit into the calc's port fully. See if the base of your plug gets obstructed by the circular lip around your calc's port.
Take the plastic cover off your 2.5mm stereo jack. It will have three connectors on the back - two small ones and one large one that wraps around everything. Thread the plastic cover onto the cable now, otherwise if you have already done the other end you won't be able to thread it on to put the cover back.
The largest of the three connectors on the back of the plug is for earth. If your cable has a copper shield as one of the wires then use this as the earth (wire shown as sleeve on diagram above). (If you have not done the computer end of this cable yet then it doesn't matter which of the other two wires you connect to which connector.)
Strip some of your cable and then solder each wire to each connector, cutting the wires to the correct lengths first of course. Hook the wires back after you have put them through the connector rings to ensure a strong connection. This step is the fiddliest of all.
You will need to know which wire you have connected to each ring on the plug. You can either find this out now or later. Use a test meter and make a note of which wire connects to what.
Carefully screw the cover back on.

Calculator end - Using a socket

If you want to use a socket then when you use your link you will use your calc-to-calc lead to go between the socket and the calculator. The method to follow is the same as above except that to work out which connector on the back of the socket connects to each ring on the plug on the far end of the calc-to-calc lead, you need to plug one end of the calc-to-calc lead into the socket and use the test meter on this combination. The combination of calc-to-calc lead and socket functions as a plug. Personally we think that using a socket is more reliable than using a plug.

Calculator end - Using half your calc-to-calc lead

In much the same way as above, to check which wire connects to what ring on the plug, you can use a test meter. You will find that the tip of the 2.5mm plug is the white wire, the middle ring on the plug is the brown wire, and the other (copper shield) wire is the ring nearest the base.

Computer end

We will prepare this end of cable for DSUB connector, connect the Printed-circuit board (if you have got) to DSUB connector's pins and put the transistors, diodes and resistors into it and get everything inside the plastic housing.
If you haven't got Printed-circuit board you can use a "joker" circuit board or you can make an "air assembly" to DSUB pins.
Investigate how your DSUB connector attaches to the housing. It may be best to work with one half of the housing attached to the DSUB connector so you can get everything the right length. Up to you.

Prepared LiYCY cable for DSUB connector:

Use the test meter to work out which wire in your cable goes to which part of your 2.5mm plug.

Carefully strip the three wires in your cable to the required lengths. Bear in mind that you will want to fit the cover over everything for neatness so don't strip them too far.

Solder the Printed-circuit board (if you have got) to DSUB connector's pins.

DD-Link panel's bottom side:

Print out the schematic: this will make it a lot easier to work with.

Solder the diodes, transistors, and resistors as shown on the diagrams above, paying attention to the polarity of the diodes.

For air assembly:

DD-Link panel's top side:

...and solder the wires to the appropriate points (see diagram above)

The ready DD-Link cable:

Check the connections, then attach the plastic housing and cable grip.

If you haven't yet done the other end of the cable now's your chance

And that's it.

Testing your link

After double checking all your connections, you need to test out your link by sending or receiving a program with appropriate Linking Software, and hopefully it will work perfectly the first time. :-) If it doesn't work, see our hints.

Good luck. See the link software page for where to get suitable link software.

Hints

Connections

First things first: check and double check that you have got the connections correct and that no wires are touching that shouldn't. Make sure you get the pin numbering correct and ensure that no pins have become soldered to each other by mistake. Check the whole thing with a test meter to check for bad connections.

Poor contact with calculator port if you use a plug

Some 2.5mm plugs do not fit far enough into the calc's port to make contact properly because of the circular 'lip' around the port on the calculator's case. To get around this you can either file away some of the metal from around the base of your plug, or you can carefully scrape away some of the plastic around the calc's port to let the plug fit in further. One person's link didn't work until he filed away a bit of the base of his plug.

Also, if you look at the plug itself on some calc-to-calc leads you will see that it's smooth all the way along. The standard type of 2.5mm plug has a groove near the tip. The grooved type should connect properly with the calc's port, however if you are having connection problems consider a socket instead (see below).

Use a 2.5mm socket instead

To ensure perfect connection with the calc's port you could use a 2.5mm socket and then use the lead supplied with your calculator to go between this socket and the calculator. This is what we would recommend. Just make sure you get a stereo 2.5mm socket.

Be careful

Obviously treat your calculator's port (and your computer's port) with respect. Check your calc's port works by transferring something to another calculator.

The computer found the cable?

You can check the cable connection by the Options=> Communication parameters window in the DD-Link!

You set the hardware parameters alike in both units?

e.g. 9600 bps, None parity, 7 bit You can see this in the Options menuitem => Communication parameters window of DD-Link and by the 4. Set hardware parameters menuitem of the Casio.

Make sure the Jack connector put in the unit is connected well

Repeated problem, that this connector is not put to totally clash, because it get stuck in the final 1 mm, with a sort of totally connection feeling. Although still stands out about 1 mm. In this case you have to turn over the SF-… unit to come the connector into better view, then must be push with bigger power, while the clearance/gap fully disappears between the root of the connector and the unit.

Windows taskbar

Please check the Windows taskbar that it includes another communication software which run right now and use the com port. (e.g. Nokia communicator PC-link software).

Power Options in Windows Control Panel

Please check the Power Options in Windows Control Panel that the UPS use the com port and please disable the UPS by selecting "none" in the UPS Configuration setting.

Frequent problems chapter

Could you downloaded and saw the Frequent problems chapter of DD-HELP.DOC file? If not click to here.

Trademarks and software names in the web pages:
CASIO is a registered trademark of CASIO COMPUTER CO., LTD. Japan,