PDP-8/E Teletype ASR-33 question

[BitWiz]

I am getting an ASR-33 in the beginning oif June and I have the following questions. I don't know if it's wired for current loop or 232 yet:

1. Can I load paper tapes even if the TTY does not have the DEC reader control mod?
2. How do I add that mod to the TTY?
3. The TTY can punch tape without printing (there's a signal on the connector for that), how can I use this from the pdp-8?
4. Which is the best paper tape text printer that doesn't use the, high speed punch, program for the 8?

Any other recommendations for running the TTY on the PDP-8. I will be running it on my 8/E until I get my 8/L up and running.

Thanks....

 

[gnupublic]

You can load RIM or BIN tapes with the loaders. The loader are faster than the 110 baud. You will need the Reader Run if you load files running Focal or Basic. They are so slow, you need to slow down.

You can add the mod using a relais (20mA) switching the START (voltage) of the reader.

You may have a look if the parity of your ASR-33 is always MARK. Maybe you have to switch it (Teletype ‍Keyboard ‍schematic ‍9334WD).

Have fun,
Volker

 

[m_thompson]

If you run OS/8 you will need to replace the TTY driver with the one that knows how to use the ASR-33 reader/punch.

 

[ftcnet]

See: DEC LT33 Mod to Teletype Model 33 ASR where your topic is extensively covered.
I think you'll find all the info you'll need there.

 

[BitWiz]

If you run OS/8 you will need to replace the TTY driver with the one that knows how to use the ASR-33 reader/punch.Do you

Do you mean for RDR/PTP? What is the device name?

How does an M8650 turn the reader on and off or is it tied directly to the clearing of the reader ready flag?

 

[DougIngraham]

Do you mean for RDR/PTP? What is the device name?

The handler is called LSPT for Low Speed Paper Tape. The device name is KS33 and the devices are PTP: for punch and PTR: for reader.

How does an M8650 turn the reader on and off or is it tied directly to the clearing of the reader ready flag?

The only time I used the paper tape on the ASR33 was in 1974 when I was in High School using an acoustic coupler and rotary dial on the phone. On that setup it was totally manual using the buttons on the paper tape part of the teletype. I don't think the M8650 or M8655 can affect the reader/punch on the teletype other than the limited use of the RDR RUN signal.

 

[BitWiz]

The handler is called LSPT for Low Speed Paper Tape. The device name is KS33 and the devices are PTP: for punch and PTR: for reader.

The only time I used the paper tape on the ASR33 was in 1974 when I was in High School using an acoustic coupler and rotary dial on the phone. On that setup it was totally manual using the buttons on the paper tape part of the teletype. I don't think the M8650 or M8655 can affect the reader/punch on the teletype other than the limited use of the RDR RUN signal.

How does the M8650 control the read run signal. Does it follow (or invert) the keyboard/reader flag so the TTY advances the paper tape when the previous character is read?

Thank you for the help Doug.

 

[BitWiz]

How does the M8650 control the read run signal. Does it follow (or invert) the keyboard/reader flag so the TTY advances the paper tape when the previous character is read?

Thank you for the help Doug.

I'm hoping to have it connected to the 8/L and have it at VCFMW to demonstrate. If not I will hook it up to either the 8/E or the PiDP-8/E

 

[djg]

How does the M8650 control the read run signal. Does it follow (or invert) the keyboard/reader flag so the TTY advances the paper tape when the previous character is read?

Yes

The TTY can punch tape without printing (there's a signal on the connector for that), how can I use this from the pdp-8?

I didn't know they could do that. All mine print when punching. PDP-8 has no provisions for driving that signal.

Which is the best paper tape text printer that doesn't use the, high speed punch, program for the 8?

Best is subjective. I assume you mean punch text as human readable. I have the ones I use for demo here. The second punches the binary ASCII so I could show the normal computer representation of the text also.
https://www.pdp8online.com/ftp/software/demos/punch_text/. There are some DECUS ones around also.

 

[MauriceH]

First, if you get the ASR33, start with replace that rubber round stamp, at the printer !.
If its very hard or broken you will destroy printer head.

Far easy to replace. I used a rubber damping stud that already so had a screw stud moulded.
Just cut it to right high and I tapped a thread in the leaver that formally hold the old one.
A small nut to secure.

You don't need to full disassemble the printer, just see how it is attached and only dismantle what is needed to get that part out.
See picture.

First setup the M8650 as seen in picture.
That is how I use the ASR33

Then I Load the BIN Loader and just start reader manually.
As I use a modem with a Phone line, as the ASR is sitting downstairs and PDP8M upstairs.

Use as RS232 the colour lines are enough, or use the official and then use all dotted lines.

From the guy who back in day's my ASR33 conversion build (As a "Koopmans Modem conversion with 200Bd modem" )
I got this about the start Reader: (I never used that function so far)
---------------------------
There were not many options of Teletype. Namely only one.
The so-called X-on/X-off function.
This was to start and stop the punch tape reader remotely with ASCII codes DC1 and DC3.
We had to mount a block on a rail with two mechanical pawls that were operated by two rods that came into action by the code bars,
when they received an X-on or X-off code (a control ASCII code).
The pawls then made an electrical contact on that block (3 x 4 x 2 cm).
A relay came in and the punched tape reader started running.
The relay was held electrically until the break contact of the X-off pawl deactivated the relay and the punched tape reader stopped again.
This was a way to give the computer the possibility to read a previously produced punched tape,with data from that day,
in pieces, for example at night.

This was often the time that the computers had computing time left to process less important data.

-------------------------

 

[BitWiz]

First, if you get the ASR33, start with replace that rubber round stamp, at the printer !.
If its very hard or broken you will destroy printer head.

Far easy to replace. I used a rubber damping stud that already so had a screw stud moulded.
Just cut it to right high and I tapped a thread in the leaver that formally hold the old one.
A small nut to secure.

You don't need to full disassemble the printer, just see how it is attached and only dismantle what is needed to get that part out.
See picture.

First setup the M8650 as seen in picture.
That is how I use the ASR33

Then I Load the BIN Loader and just start reader manually.
As I use a modem with a Phone line, as the ASR is sitting downstairs and PDP8M upstairs.

Use as RS232 the colour lines are enough, or use the official and then use all dotted lines.

From the guy who back in day's my ASR33 conversion build (As a "Koopmans Modem conversion with 200Bd modem" )
I got this about the start Reader: (I never used that function so far)
---------------------------
There were not many options of Teletype. Namely only one.
The so-called X-on/X-off function.
This was to start and stop the punch tape reader remotely with ASCII codes DC1 and DC3.
We had to mount a block on a rail with two mechanical pawls that were operated by two rods that came into action by the code bars,
when they received an X-on or X-off code (a control ASCII code).
The pawls then made an electrical contact on that block (3 x 4 x 2 cm).
A relay came in and the punched tape reader started running.
The relay was held electrically until the break contact of the X-off pawl deactivated the relay and the punched tape reader stopped again.
This was a way to give the computer the possibility to read a previously produced punched tape,with data from that day,
in pieces, for example at night.

This was often the time that the computers had computing time left to process less important data.

-------------------------I have the unit now and I have the following questions

I was given an ASR-33 complete with stand, reader & punch. The reader power supply is under the connect cover on the right hand side, not in the stand.

This ASR-33 has been modified for RS-232 though a blue perfboard mounted in the connection enclosure (under the cover place where the dialer would be on the right side).

It has a DB25 ribbon cable coming off of this board. The perfboard does not have a label on it that I can find.

The ASR-33 also has a 3 x 5 conductor rectangular connector coming out of the rear of the unit with 6 female contacts installed.

I was able to connect the ARS-33 to a VT-330+ at 110B 8-N-2 and send and receive on the teletype.

The punch seems to work as well.

The reader will "chatter" then the reader is put in the start position and the tape out sensor is pressed but the sprocket does not advance and the reader pins to not move.

Questions:

1. Why the reader is not advancing and the pins are not activating? Could this be a read enable contact not being in the active position?
2. What are the pin outs of the RS-232 DB-25. Other than TX, RX and GND
3. What are the pin outs of the 3 x 5 rectangular connector. I think this is the current loop and other control signals.

Does any one of the items below for sale or have a 3D model I can print:

1. Roll Paper spindle (the spindle that the roll paper spins on)
2. Paper Tape Punch Spindle (the spindle that the paper tape spins on)
3. Paper Tape Chad feed tube
4. Paper Tape Chad Box
5. Replacement pad that hits the type cylinder.

I will be connecting this to either a PiDP-8/I or a PDP-8/E for now and eventually a PDP-8/L


Thank you,


Mike

 

[djg]

Why the reader is not advancing and the pins are not activating? Could this be a read enable contact not being in the active position?

From memory the reader uses rectified line voltage to drive the magnet. For mine reader stopped working when the capacitor died. Open contacts could also cause it.

For external connectors they tended to be made by users so don't have standard pinouts.

 

[BitWiz]

From memory the reader uses rectified line voltage to drive the magnet. For mine reader stopped working when the capacitor died. Open contacts could also cause it.

For external connectors they tended to be made by users so don't have standard pinouts.

The reader issue is that the reader power pack board is missing. I think whoever did the RS-232 conversion removed it.

If I can figure out all of the voltages I may try to build one.

Do any of you have a spare power pack board (183087) .

I don't know if the reader power pack board for automatic reader operation (183079) will work or not.

I'm still looking for the following items for the ASR-33

rubber hammer (180502)
paper spindle (181043)
paper tape spindle (183918)
paper tape ends (182935)
chad box (182924 or 182965)

Thank you,

Mike

 

[BitWiz]

The reader issue is that the reader power pack board is missing. I think whoever did the RS-232 conversion removed it.

If I can figure out all of the voltages I may try to build one.

Do any of you have a spare power pack board (183087) .

I don't know if the reader power pack board for automatic reader operation (183079) will work or not.

I'm still looking for the following items for the ASR-33

rubber hammer (180502)
paper spindle (181043)
paper tape spindle (183918)
paper tape ends (182935)
chad box (182924 or 182965)

Thank you,

Mike

My problem turned out to be a missing Reader Power Pack. I have one on order now.

I'm thinking of using the Automatic Reader Power Pack to connect to the reader run output of the M8650 using a current loop to relay circuit.

Thanks...

 

[BitWiz]

Related question.

If the M8650 is jumpered for RS-232 will the RR+ and RR- signals still appear on the connector?

 

[gnupublic]

Here
are some hints of modification of the M8655/M8650 for using the RR even with RS232. Together with gtty you get an ASR33 like tool on a modern PC with much higher baud rate.

And yes, the RR signal is still there. You can feed the ASR-33 with it.

 

[BitWiz]

Here
are some hints of modification of the M8655/M8650 for using the RR even with RS232. Together with gtty you get an ASR33 like tool on a modern PC with much higher baud rate.

And yes, the RR signal is still there. You can feed the ASR-33 with it.

I am thinking of using the Automatic Read Power Pack board and building a circuit to convert the current loop Read Run signal to a contact closure type that the teletype uses.

I will check out that article. Thank you.