Using an external audio recorder
( Detailed operating instructions )
|Using a standard audio cassette recorder|
The ideal situation is to use Sharps own MZ-1T01 ( for MZ-700 ) / MZ-1T04 ( for MZ-800 ) data recorder which can be built in to the MZ-711 / MZ-811, but it may be that, having spent all your savings on the basic computer, you cannot afford the data recorder as well. Let me say straight away that there are problems involved in using a standard audio cassette recorder, and in this section I shall attempt to point out the pitfalls involved.
If you are using an audio cassette recorder which you have had for some time, it is advisable to clean the recording head because the recording quality may be critical - proprietory cleaners of the tape or swab kind are available.
Next you need some means of linking the computer to the recorder. Most recorders have sockets for 3.5mm or cinch jack plugs, one labeled MIC(rophone) and another labeled MONITOR, SPEAKER or EAR(phone). The computer also has two cinch sockets in the rear panel just below the TV connection sockets, one labelled READ, the other WRITE.
Most hi-fi dealers will be able to supply you with an audio twin core cable, with the two plugs at each end you need. They are usually colour coded so that you can follow the route of each wire. Dont buy too long a lead, because the longer it is, the more prone it will be to picking up interference. The actual length will be influenced by the location of your cassette recorder relative to the computer, but I suggest 18 inches ( 45cm ) should be the maximum.
Connect the WRITE socket of the computer, following the wire through to the MIC socket of the cassette recorder. The plugs on the other cable should then be used to connect the computers READ socket and the recorders EAR socket.
If the cassette recorder has a mains or battery power option, it would be preferable to use it from the mains, so that recording or playback is not affected by battery strength.
lf you have any choice in the selection of the cassette recorder you are going to use, it would be advisable to pick one which has a tape counter, which is extremely valuable when several programs are recorded on one tape.
Having connected the cassette recorder set the volume control ( and tone, if any ) to the mid point; then switch on the mains supply, turn on the computer and type L. With the MZ-811 you may find it more successful to type only C or M and then L from Monitor.
When you press CR the cursor will simply stop flashing - you will not get the prompt PLAY. Press the PLAY key on the cassette recorder and wait, with bated breath! In a few moments you should see the message LOADING S-BASIC ( MZ-800: "IPL is loading MZ-1Z016" ) appear on the screen. If you dont, wait a while longer, but if it still doesnt appear, stop the recorder and wind it back. Press the computers SHIFT and BREAK keys simultaneously, then set the volume control on the recorder to a slightly higher level and try again.
Super high-fidelity is not necessary in recording for the computer as it ignores the subtleties in the recorded sound, so a cheaper cassette recorder may perform better than a deluxe model. lt may require a good deal of experimenting with the volume control ( and tone, if fitted ) until you can LOAD successfully.
If, having tried conscientiously for some time, you are still unable to load BASIC, you may need to reverse the polarity switch inside the computer. Fortunately for MZ-811 owners the polarity switch is outside the casing so it is not necessary to dismantle the computer as described below. Polarity is changed by system switch 4 at the rear of the computer
To do this, first disconnect the computer from the mains power supply and then remove the cassette compartment cover ( at the right hand side of the computer when viewed from the keyboard side ) by unscrewing the two cross-headed screws at the back. You will see a large metal box ( the TV modulator ) and to the left of this a small slide switch. Simply push it across, replace the cover and then follow the loading procedure again. lf you still cannot succeed in loading BASIC borrow a different cassette recorder and see whether this produces a more successful result.
Assuming that you have now managed to load BASIC, you will note that the tape keeps turning - you will have to stop it manually. Even though you may have a socket on the cassette recorder which usually permits remote control, this cannot be used with the computer. The procedure given here for LOAD and SAVE will generally apply, except that no prompts are given and the tape motor is not controlled by the computer.
When you enter a SAVE command you must remember to press both RECORD and PLAY keys, and watch for the Ready message, which is your cue to stop the tape. When you VERIFY programs you have just SAVEd, there is no prompt to press the PLAY key. While experimenting with the MZ-700 using a standard cassette recorder, I found that VERIFY would sometimes return a READ ERROR message, and yet when I cleared the memory, the program in question still loaded successfully from tape. However, another cleaning of the recording head seemed to overcome that problem.
The MZ-700 Owners Manual suggests that:
When an ordinary cassette recorder is used, it may not be possible to record data files even if no problems are encountered in storing or reading programs with the SAVE and LOAD commands ( the same warning applies to the MZ-800 ).
Theyre not kidding! If you want to write programs which rely on saving data on separate tape files, try out a very short program first. lf my experience is anything to go by, the odds are that it wont york. I found that although the data tape seemed to record successfully ( and of course it is not possible to VERIFY it ) it proved impossible to use the data tape in a program designed to read it.
lt seems, therefore, that you may have to content yourself with using your audio cassette recorder purely for LOADing and SAVEing programs. However, that is the main requirement for use with a computer, so you should be able to manage until you have saved enough to buy your Sharp MZ-1T01 / MZ-1T04 data recorder, and then you can find out from the next menu item how to install it.
bad news is that programs you have previously recorded may well not
load properly when using the data recorder. lt is normally advisable
to stay with the same recorder for all your work and so I would
recommend that you obtain a Sharp data recorder as soon as possible.