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Interested in punched tape

kyeakel

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I would like to add a punched tape reader capability to my s100 computers. What should I be looking for as far as interface cards, and the reader itself? Can the CNC punched tape readers be used? They seem to be much more available, and some are cheap. Back in the early 80's I replaced the paper tape readers we used to load test equipment programs, by using an IBM-PC parallel port. The PC could also read the tapes by hooking the parallel port to the reader. I would eventually want a punch as well, but thought I could start by loading basic via tape.

Kipp
 

Chuck(G)

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Interface varies, but you can get both serial and parallel tape readers and both can be made to work on an S100 system, given the proper interface. Fortunately, parallel interfaces aren't hard to come by in that form--and neither are serial. Be aware, however, that a serial tape reader is likely to be current-loop.

There are more modern DIY versions as well.
 

glitch

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I'm in the process of interfacing a high speed optical reader from a HP minicomputer to the S-100 bus. The interface is really simple, just 8 data bits, a data strobe and EOT coming from the reader, and a READ signal that engages the roller clutch to the computer. More details as that comes along.

There are a number of "hobbyist" readers from the S-100 era...at one point, I had an Oliver Audio reader, which is a neat optical reader made mostly with 555 timers. It uses external illumination, usually from a desk lamp. In testing it (unfortunately, I've sold it...wished I hadn't now!) I found it pretty tolerant of light source and couldn't pull the tape fast enough by hand to get read errors from a PC parallel port under Linux.

Yes, you can use the CNC punched tape readers if you're willing to design the interface yourself.
 

MikeS

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I've got four or five readers somewhere that I've been meaning to look at; maybe this'll be the inspiration...

Also some perforators, but they're a little trickier and one (an NCR) weighs at least 25 or 30 lbs.
 

Erik

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The CNC readers are a good choice. Most of those are higher speed (1200-2400 baud) and read and punch quicker than the 110 of a TTY.

Most are also serial interface units although, as Chuck said, some are current loop to match the teletypes they replace.

I've got one with a serial interface that I use for most of my higher volume punching. It'll connect to my PC or almost any of my vintage gear.
 

g4ugm

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I have a couple of GNT CNC reader/punches I bought on E-Bay "as-seen". The readers work fine in both but one of the punches has a bad column. They have RS232 serial ports and work great on an old Windows/2000 box for reading tape into Hyperterm.
 

tingo

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So what are the magic words for finding cheap / reasonable priced CNC tape readers on eBay? I tried "CNC tape reader" and such, but only got readers from USD 175 and up.
 

Erik

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So what are the magic words for finding cheap / reasonable priced CNC tape readers on eBay? I tried "CNC tape reader" and such, but only got readers from USD 175 and up.

In that arena $175 is reasonably priced. I've seen them for $500 plus. IIRC mine was $150 refurbed 5 years ago.
 

Chuckster_in_Jax

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So what are the magic words for finding cheap / reasonable priced CNC tape readers on eBay? I tried "CNC tape reader" and such, but only got readers from USD 175 and up.

I've been somewhat interested in punched paper tape also. I see a lot of readers but few that actually do the punching. It also seems you need some knowledge of capturing data coming across RS232 as well as building an interface. Don't know how many of those units on eBay come with an rs232 interface.
 

g4ugm

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I've been somewhat interested in punched paper tape also. I see a lot of readers but few that actually do the punching. It also seems you need some knowledge of capturing data coming across RS232 as well as building an interface. Don't know how many of those units on eBay come with an rs232 interface.

You sound a bit dispirited! What computers would you like to use paper tape with?

If the punch/reader is RS232 (that's normal old fashioned async serial) then many (most?) vintage computers already have such a port so you don't need to build an interface. There is one on my Atari ST, TT and Mega. My old Newbury 6809 machines had serial interfaces. My new(ish) Core I5 Windows/7 PC now has two serial ports thanks to the wonders of E-bay and a PCI Express dual serial card.

Even if it doesn't have an obvious serial port then it may be possible to provide one with minor mods. Many machines have a cassette interface which is just serial data so it may be possible to extract he signal and use a couple of MAX232 chips to convert to RS232. If you do need to build a serial interface then I am pretty sure there are designs for almost everything on the net.

As for "knowledge of capturing data" then again many computers already have the routines build in. They were designed to work with ASR33 TTYs with punches, or with cassette tape interfaces and so there are routines to save to tape.

On Windows then you can use Hyperterm (if you don't have HyperTerm then there are plenty of instructions on the net on how to copy from an old Windows disk) to simply capture the data session to disk. (not sure if PUTTY will do the same on Linux)

If its a parallel reader then the fun starts. You may have to design an interface, and you may have to write code, but its not hard code....

As for punches, then there is a nice looking Facit on Ebay but I wouldn't pay $250 for something sold as untested. I paid around $50 each for my GNTs and one has a a dead hole on punch...

Dave
 

kyeakel

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Well I bought an Addmaster 612-2 punched tape reader for a Cnc machine that was in need of electronic repair. It cost $49 + shipping and took me about 3 hours to fix and figure out the dip switches without any manual. So, it now works and I can dump a tape to a PC serial port by loading the tape, and then setting DTR. I also bought some Altair tapes from the marketplace. Now I need to get a serial port working on one of my s-100 machines. I'm waiting on parts for an IMSAI SIO, then after coding a loader, I should be in buisness.

Kipp
 

Chuckster_in_Jax

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You sound a bit dispirited! What computers would you like to use paper tape with? If the punch/reader is RS232 (that's normal old fashioned async serial) then many (most?) vintage computers already have such a port so you don't need to build an interface.

Probably an S-100 machine like a Cromemco Z-2D or Compupro 8/16 or even a Heathkit H8. Any of these have RS232 boards in them and would be in the era that used punched paper tape. So I would need to find a paper tape unit with a serial interface.

As for "knowledge of capturing data" then again many computers already have the routines build in. They were designed to work with ASR33 TTYs with punches, or with cassette tape interfaces and so there are routines to save to tape. On Windows then you can use Hyperterm (if you don't have HyperTerm then there are plenty of instructions on the net on how to copy from an old Windows disk) to simply capture the data session to disk. (not sure if PUTTY will do the same on Linux)

OK, how is the information interpreted by the computer? Is the program on the paper tape in machine code or can it be in BASIC ... or what?

Chuck
 

g4ugm

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OK, how is the information interpreted by the computer? Is the program on the paper tape in machine code or can it be in BASIC ... or what?

That depends on what you saved on the paper tape. Just like a disk file the tape can contain ASCII text or Binary data. So if its a basic source program then its usually just ASCII source of the program. If its machine code then its usual to encode it in some way, so that you have the load address. For a 8080/z80 machine Intel Hex format would be most common. For a 6800/6809 Motorola S9 format. Some tapes I have just read for some one had some program source and program output as ASCII text.
 

kyeakel

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My plan for loading is to write an assembly routine that will reside in eprom. This program will use the desired starting address as a front panel input, and then load the contents of the tape (in binary) starting at that address. I have 8k ram right now but another 24k on the way. So I'd locate it above that. Setting the address on the imsai front panel and then running from there. The other option is to use 2 serial ports, 1 for the tape reader and the other for a terminal. I could then enter the address and other parameters from the terminal.

Kipp
 

MikeS

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I'd think that if you didn't create the tape then your load routine would have to match the format of the tape; as Dave points out, most tapes would be either ASCII text or Intel hex, neither of which is really what I'd call pure binary (i.e. a contiguous sequential file of 8-bit bytes, without address info, checksums etc.)
 

g4ugm

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The trouble with pure binary is knowing when to start, when to stop, and deciding if you have done it properley. So I would have at least a 2-byte length, (LSB first) the code and a two byte checksum. However being lazy I would do a google search for Intel Hex Loader and "borrow" that code.
 

kyeakel

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Some of my web searches have turned up things like: the Altair basic loads the first part in binary, then it jumps to that code to decode the rest. I have also seen instructions to stop the machine after the tape loads via the front panel switches and then restart at some address. The Tarbell cassette interface seems to say load the program, and wait for several seconds to be sure it's done. These methods are somewhat crude but sounded plausible to me. If the tape is in some other format, I agree it will have to be decoded. Having it stored in Intel hex format would seem to increase tape length by quite a bit. The only reason I can see to do this would be to gain the offsets and check summing. Either way it's just an extra subroutine or two..

Kipp
 
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