Interfaces of IBM and PC-1475

Index

• 15 pin interface
• 11 pin interface
• Serial Interface at IBM-PC
• Hardware Ports of PC-1475

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1	protective ground for repairs	(not used)		-
2	transmit data	SD		out
3	receive data	RD		in
4	ready to send	RS	(HIGH: sends carrier)	out
5	clear to send	CS	(HIGH: transmits)	in
7	ground	GND	(level 0 for transfer)	-
8	carrier detected	CD	(HIGH: carrier detected)	in
10	5 volts	VC	power supply	-
11	ready to receive	RR	(HIGH: receiving possible)	out
12	periph. signals	PAK	(for serial printers from SHARP)	in
13	5 volts	VC	power supply	-
14	data terminal ready	ER	(HIGH: data terminal ready)	out
15	periph. signals	PRQ	(for serial printers from SHARP)	out

The pocket doesn't use all of these pins:
Pin 5 high is enough to make it send data.
On pin 11 only it tells that it's ready for receiving data.

PC-1475 printer interface 11 pin IO

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1	not used	-		-
2	+6V	VCC	Power supply	-
3	Ground	GND	ground	in
4	line	-	Use address &3800-FF: see ports	out
5	line	-	Use address &3A00-FF: see ports	out
6	LOAD	-	Used by CLOAD, you can get this line through TEST 128	in
7	SAVE	-	Used by CSAVE, you can set this line through port C, bits 4,5 and 6	out
8	line	-	B port/Use address &3A00-FF: see ports	in/out
9	line	-	B port: see ports	in/out
10	line	-	Use address &3A00-FF: see ports	out
11	line	-	Use address &3A00-FF: see ports	out

Desktop-PC serial interface 9/25 pin IO

9 pins	25 pins	Name	Description	Direction
1	8	CD	Carrier Detect - Modem has carrier and is online	in
2	3	RxD	Receives data	in
3	2	TxD	Sends data with +12V at HIGH and -12V at LOW	out
4	20	DTR	Data Terminal Ready - computer is ready for receiving data	out
5	7	GND	Ground	-
6	6	DSR	Data Set Ready - The other computer is ready to receive	in
7	4	RTS	Request To Send - This line makes the other to get ready for receiving	out
8	5	CTS	Clear To Send - When the other RTS sends HIGH to this line the computer starts transmitting	in
9	22	RI	Ring - an incoming call is detected by the modem	in

Hardware ports

Address &3800-FF = 14336 (only output)

Address &3A00-FF = 14848-15103 (only output)

Port B (&5D = 93 internal RAM)

Port F (only output, &5E = 94 internal RAM)