Transferring files

Null Modem to Xfer Files

If you have ever had the need (or desire) to connect your Kaypro to another Kaypro (or another computer) to transfer files and you don't have a modem, here is a scheme to connect two together which makes each think it is using a modem. You will also be able to transfer data at much higher rates than the standard 300 or 1200 baud that most modems afford.

If you have an existing RS-232 cable that you don't need for another purpose (I got mine at a swap-fest), make the following changes with a small (20-25 watt soldering iron.

ON ONE END OF THE CABLE ONLY, unsolder the wires from pins 2 and 3, then reverse these two and re-solder them. Unsolder the wires from pins 5 and 8, then reverse these two and re-solder them. Unsolder the wires from pins 6 and 20, then reverse these two and re-solder them. ON BOTH ENDS OF THE CABLE, unsolder the wire from pin 4 and fold it back so it will be out of the way. Don't cut the wire, so you can return the cable to its original configuration should you ever desire. Then solder a small bare piece of solid copper wire lying across pins 4 and 5, forming a jumper between the two. Check all connections to insure that you made each change correctly, then reassemble the hoods on the 08-25 connectors.

If you don't already have an RS-232 cable which you can modify, you can make one up from a length of (at least) nine conductor cable and two DB-25 connectors. Follow the wiring diagram below, noting that pins 4 and 5 at each end of the cables are jumpered together.

NULLMODEM

DB-25 connector	cable	DB-25 connector
PROT GND	1------1	PROT GND
XMTD DATA	2------3	RCVD DATA
RCVD DATA	3------2	XMTD DATA
REQ TO SEND	4-+
CLEAR TO SEND	5-+----8	RCVD LN SIG DET
DATASET RDY	6---20	DATA TERM RDY
SIGNAL GROUND	7----7	SIGNAL GROUND
RCVD LN SIG DET	8--+-5	CLEAR TO SEND
	+-4	REQ TO SEND
DATA TERM RDY	20---6	DATA SET RDY

With the cable completed, plug one end into the RS-232 connector on the back of each computer labeled J3 MODEM I/O. Many communications programs can be used, but the use of SUPRTERM will be described here. Load a disk with SUPRTERM into drive A: on both computers, a disk with the files into drive B: on one computer, and a blank formatted disk to receive those files into drive B: on the other computer. Then, on both computers, type A:ST, and you will see the following one-line menu (on two lines here due to column width):

ST v 5 Command? (<ESC>/Break/Cmdfile/Dial/List/Print/Recv/Send/Term/Quit)?

Then, on both computers, type T, and you will see the following menu:

ST v 5 TERM Option?(<ESC>/Baud/Duplex/Echo/Format/Nulls)?

Again on both computers, type B to get the following menu:

TERM BAUD Rate?(<ESC>/A=110/B=300/C=600/D=1200/E=2400/F=4800/G=9600/H=19.2K)?

On both computers, select G to set the baud rate at 9600K. Press RETURN once to get back to the TERM Option menu, then again to get back to the Command menu.

Then on the receiving computer, press R to get the following menu:

ST v 5 RECV Option? (<ESC>/Addlf/File/Lowup/onOFF)?

Press F to get the following:

RECV FILE Mode? (Block/Terminal)?

Press B, and you will see this:

ST v 5 RECV FILE Name?

Now enter the name of the file you intend to receive from the other computer. Wild cards, such as B:*.BAS, B:A????.*, etc., are acceptable. Press RETURN after the file name, and you will see:

ST v 5 RECV Option? (<ESC>/Addlf/File/Lowup/onOFF)? BF=B:(filename.ext)

Then press O, and you will see this:

ST v 5 RECV CRC? (Crc/Nocrc/Abort)? BF=B:(filename.ext)

Press C to invoke cyclic redundancy check (an error checking routine), and the following will appear:

WAITING FOR FILENAME... (Press Control X to Abort)

followed by a directory listing of all the files on drive B: (if that is the drive you specified) which match the FILENAME you entered.

Now on the sending computer, from the Command menu, press S and you will see this:

ST v 5 SEND Option? (<ESC>/Addlf/File/Lowup/onOFF/Remlf)?

As with the receiving computer, press F to see this:

SEND FILE Mode? (Block/Terminal)?

Press B, and you will see this:

ST v 5 SEND FILE Name?

Now enter the name of the file you intend to send to the other computer. Wild cards, such as B:*.BAS, B:A????.*, etc., are acceptable. Press RETURN after the file name, and you will see:

ST v 5 SEND Option? (<ESC>/Addlf/File/Lowup/onOff)? BF=B:(filename.ext)

Press O, and you will see:

SENDING B:(filename.ext) [...]
followed by a directory of all the files which match the FILENAME you entered before. If all went well, you will see:

SEND FILE TRANSMITTED OK AND CLOSED....
on the sending computer, and:

RECEIVE FILE TRANSMITTED OK AND CLOSED....
on the receiving computer. Pressing return will put you back to the SEND Option or RECV Option menu. If you want to continue, press F, then B, then enter the FILENAME of the next file you wish to send/receive. If you are through, press RETURN once more to get back to the Command menu, then Press Q to quit. Like most software manuals, the one for SUPRTERM seems to assume that most of us know more than we actually do, but a little diligence coupled with some experimentation will see you through other types of file transfers after you have accomplished this Kaypro-to-Kaypro transfer.
(Mike Patton, Kugram, Mar/Apr 1985)