A Made IT project

IEEE 488

General
An HP bidirectional parallel printer interface capable of handling 15 devices @ 500 kBps.
The maximum distance = number of devices * 2 meters with an absolute maximum of 20 meter.

The above specifications seem confusing (and they are), but it is the most accurate documentation we have!

The bus consists of one controller and 1 to 15 devices in a daisy chain fashion shown in the picture below:

An IEEE 488 device has per device 4 different addresses for Command, Listen, Talk and Secondary. Let's say we have a plotter on address 0 then his addresses would be:

00 = Command Address
20 = LISTEN Address
40 = TALK Address
60 = Secondary Address

Male	Female

Pin	Signal	Abbr.	Source
1	Data Bit 1	DIO1	Talker
2	Data Bit 2	DIO2	Talker
3	Data Bit 3	DIO3	Talker
4	Data Bit 4	DIO4	Talker
5	End Or Indentity	EOI	Talker/Controller
6	Data Valid	DAV	Controller
7	Not Ready For Data	NRFD	Listener
8	No Data Accepted	NDAC	Listener
9	Interface Clear	IFC	Controller
10	Service Request	SRQ	Talker
11	Attention	ATN	Controller
12	Shield		-
13	Data Bit 5	DIO5	Talker
14	Data Bit 6	DIO6	Talker
15	Data Bit 7	DIO7	Talker
16	Data Bit 8	DIO8	Talker
17	Remote Enabled	REN	Controller
18	Ground DAV		-
19	Ground NRFD		-
20	Ground NDAC		-
21	Ground IFC		-
22	Ground SRQ		-
23	Ground ATN		-
24	Logical Ground		-

Technical Description
The bus is TTL active low (open collector). Every device which asserts a signal low will override the high from another device.

Resources: