ndeng@EULER.BERKELEY.EDU (10/25/89)
I heard some peripherals use an "IEEE-488 interface" instead of RS232 serial or Centronics parallel. What is it? Is this interface compatible to RS232? Do I need to buy a special card for this interface in case I have a device to use on my pc? Wher can I get the card? any recommendations?
kens@hplsla.HP.COM (Ken Snyder) (10/26/89)
> I heard some peripherals use an "IEEE-488 interface" instead of RS232 serial > or Centronics parallel. What is it? Is this interface compatible to RS232? > Do I need to buy a special card for this interface in case I have a device > to use on my pc? Wher can I get the card? any recommendations? The IEEE-488 interface, also known as the HP-IB (here at HP where the standard was invented) is an 8 bit parallel interface with special handshaking and other lines to implement a fast bus between instruments and computers. It also has a specific protocol associated with how the control lines are used. You cannot "kludge" an interface to RS-232 or centronics parallel by simply rewiring the connector. There are a few vendors who make HP-IB interface cards for the pc. HP is one of them, National makes one and I believe IBM. I use HP's (for obvious reasons) to drive my printer and a plotter with HP-IB interfaces. Go fer it, Ken
bb16@prism.gatech.EDU (Scott Bostater) (10/26/89)
In article <8910250801.AA04854@euler.Berkeley.EDU>, ndeng@EULER.BERKELEY.EDU writes: > > I heard some peripherals use an "IEEE-488 interface" instead of RS232 serial > or Centronics parallel. What is it? Is this interface compatible to RS232? > Do I need to buy a special card for this interface in case I have a device > to use on my pc? Wher can I get the card? any recommendations? IEEE-488, GP-IB, and HP-IB all refer to an interface standard that is used primarily by lab equipment. It allows a computer (bus controller) to communicate with O-scopes, multimeters, spectrum analyizers, etc. Other non- typical lab equipment would include printers and plotters. The purpose of the bus is to help automate experiments by providing a standard interface to almost lab equipment. The bus has nothing to do with RS232. It is an eight bit parallel bus utilizing a 3-wire handshake protocol. A large percentage of lab equipment that has a IEEE-488 interface will also allow for RS232 communication, however, this would normally only work with 1 piece of equipment. The IEEE-488 bus allows up to 32 different pieces of equipment to be on the bus at one time. The 3-wire handshake means that the bus is slower than a standard parallel card (and totaly incompatible), the bus essentially runs at the speed of the slowest active device on the bus. Yes, you will need to buy a special card to use the IEEE-488. Metrabyte sells two diffent cards in the $200-$400 range. Data Translation, National Instruments, and others also sell them. As far as recommendations go, I own a Metrabyte card and haven't tried any of the others so I can't really comment. -- Scott Bostater GTRI/RAIL/RAD (Ga. Tech) "My soul finds rest in God alone; my salvation comes from Him" -Ps 62.1 uucp: ...!{allegra,amd,hplabs,ut-ngp}!gatech!prism!bb16 Internet: bb16@prism.gatech.edu
cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) (11/03/89)
In article <8910250801.AA04854@euler.Berkeley.EDU> ndeng@EULER.BERKELEY.EDU writes:
$I heard some peripherals use an "IEEE-488 interface" instead of RS232 serial
$or Centronics parallel. What is it? Is this interface compatible to RS232?
$Do I need to buy a special card for this interface in case I have a device
$to use on my pc? Wher can I get the card? any recommendations?
IEEE-488 (a.k.a. GPIB for General Purpose Interface Bus or HPIB for HP)
is an 8-bit parallel bus standard allowing for one or more bus masters and
several slaves (I'm not sure what the maximum is). It is typically used
for controlling instrumentation, although it can be used for other tasks
(if you ever used Commodore PETs, their disk drives and printers were all
hooked up to it by GPIB). Oh, it's fully bidirectional.
The standard specifies the signal lines, levels, etc ... everything right
down to the size and shape of the connector to be used. It's a dual-headded
connector, so to plug two connectors onto one device, you first plug one
connector onto the device, then you plug the second connector into the first.
A pretty good scheme, except that if you get a whole string of them, you
have to prop them up (even though they're held in by screws, they still
tend to twist and occasionally break contact).
You'll need a special card for your PC and some software in order to
use this standard. If you look through BYTE or similar magazines, you'll
find lots of ads for GPIB boards and software for PCs.
-Steve
--
Stephen M. Dunn cs4g6ag@maccs.dcss.mcmaster.ca
<std_disclaimer.h> = "\nI'm only an undergraduate!!!\n";
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They say the best in life is free // but if you don't pay then you don't eatkarl@ddsw1.MCS.COM (Karl Denninger) (11/03/89)
Another note on GPIB (IEEE-488): I used to work for a company that made embedded controllers. You wouldn't believe how difficult it is to do a truly complete IEEE implementation. It is a REAL bitch to handle the multiple master/slave stuff, and do it properly, not to mention polling and all the other subtleties of that interface. EVERY piece of equipment that I have seen (and that is dozens, including some mdade by HP) either took the easy way out and said "ok, this is all we handle" or botched it in some way. NONE were consistant. Single-master IEEE interface busses are relatively easy to deal with. Multiple master, especially those in which any device can decide it wants to be bus master at any time, are a lot of fun. I haven't checked out the PC-type boards in detail, but there are several that work. The good ones are NOT cheap. In fact we sell one; it's somewhere in the area of $300-400 with the software (MSC library). As for how good it is? I have no idea.... but one of our customers buys a lot of them. -- Karl Denninger (karl@ddsw1.MCS.COM, <well-connected>!ddsw1!karl) Public Access Data Line: [+1 312 566-8911], Voice: [+1 312 566-8910] Macro Computer Solutions, Inc. "Quality Solutions at a Fair Price"