Sanity check for setup

General discussions related to the Altair 8800 Clone

Sanity check for setup

Postby Semolina » August 12th, 2015, 3:01 pm

Hello!

I've been interested in vintage computing for a while, and I have never used anything older than a C64 and I'm really considering this Altair Clone. Just got a few questions for minor details and hopefully the experts here can laugh, er, help teach me where my ideas will go wrong.

1. I'd like to use a dedicated terminal to try to recreate what a hobbyist would have used in the late 70s, and learning what I need to learn in the process. A DEC VT100 would be my dream setup, but I don't know if that's accurate. Most examples I've seen use a terminal emulator on a modern PC. Are there any gotchas lurking for trying to use that kind of hardware? As I understand it, I just have to make sure the terminal supports 9600 baud 8N1, and I can use an ASCII keyboard... is that right?

2. I have an old cassette recorder with line in and line out. Will the cassette interface work with the usual three-conductor 1/8" TRS connectors or will I have to get mono ones?

3. It sounds like anything connectable via serial port using the right settings will work, and is controlled by a UART. Is that right? What's the voltage swing?

4. What texture is the front panel? I'm serious: octal is still kind of a foreign language to me and I think better in hex. I'd like to cut some strips of label paper and stick it between the switches/LEDs to make 4 groups of 4, instead of 5 1/3 groups of 3. I actually haven't decided, I might embrace octal anyway, but options are nice. :)
Semolina
 
Posts: 4
Joined: August 11th, 2015, 9:46 pm

Re: Sanity check for setup

Postby toml_12953 » August 13th, 2015, 7:02 am

Semolina wrote:Hello!

I've been interested in vintage computing for a while, and I have never used anything older than a C64 and I'm really considering this Altair Clone. Just got a few questions for minor details and hopefully the experts here can laugh, er, help teach me where my ideas will go wrong.

1. I'd like to use a dedicated terminal to try to recreate what a hobbyist would have used in the late 70s, and learning what I need to learn in the process. A DEC VT100 would be my dream setup, but I don't know if that's accurate. Most examples I've seen use a terminal emulator on a modern PC. Are there any gotchas lurking for trying to use that kind of hardware? As I understand it, I just have to make sure the terminal supports 9600 baud 8N1, and I can use an ASCII keyboard... is that right?


I have an TRS-80 Model 4D with a terminal program and a Teletype ASR-33 that I use with the Clone. I had an ADM-3A but sold it. The only problem with using an actual terminal is when you have to update the CMOS or change floppy disk images you have to disconnect the real terminal and connect a PC that can transfer files. Most standalone ASCII keyboards used a parallel interface, not serial. The Clone has no such interface (a serious lack, IMHO) so you'd have to provide your own parallel-serial converter.

2. I have an old cassette recorder with line in and line out. Will the cassette interface work with the usual three-conductor 1/8" TRS connectors or will I have to get mono ones?

I've used both with equal success.

3. It sounds like anything connectable via serial port using the right settings will work, and is controlled by a UART. Is that right? What's the voltage swing?

I've used many serial devices with the Clone such as a paper tape reader/punch. The Clone seems to use standard RS-232 protocols. I don't know the voltages, though.

4. What texture is the front panel? I'm serious: octal is still kind of a foreign language to me and I think better in hex. I'd like to cut some strips of label paper and stick it between the switches/LEDs to make 4 groups of 4, instead of 5 1/3 groups of 3. I actually haven't decided, I might embrace octal anyway, but options are nice. :)


The front panel is very smooth and takes labels well. I'd use removable labels, though, since you may find most machine language listings for Altair are in Octal and it's better to think in Octal directly than to translate on the fly (just as in human languages).

Tom L
toml_12953
 
Posts: 163
Joined: June 7th, 2013, 12:54 pm

Re: Sanity check for setup

Postby Drunkle » August 13th, 2015, 8:19 am

I'll add my two cents...;)

toml covers most of your questions well. In my case I'm using a Wyse 50 type Terminal on one serial port and an Okidata serial printer on the second serial. I have had no problems (other than the normal finding the right volume setting on playback) using old records like your for tape stuff. I also sometimes use the third serial port that comes with the tape interface card for projects needing a serial port.

If you have not already done so, have a look in the share your pictures thread on this forum where you can see my and other setups.

For the voltages question, Mike is using one of the versions from Maxum of MAX232 RS-232 driver chips. These chips normally use a +/- 9 volt swing in to normal serial interfaces type load. It should work with most normal serial devices.

Also, to take full advantage of all the versions of software used on the Altair 8800 over time, you will also need to support 7 bits with parity in addition to the normal 8N1.
Drunkle
 
Posts: 27
Joined: February 12th, 2015, 12:05 am
Location: Circle Pines, MN

Re: Sanity check for setup

Postby mail@gabrielegan.com » August 13th, 2015, 11:40 am

I agree with all the advice given so far. I've got a bunch of different old dumb terminals connected to Altair clones and so far I haven't come across a DB-25 connector on a dumb terminal that wasn't straightforward RS-232 and they've all worked fine with the Altair. (Sometimes the DB-25 port on the terminal is labelled 'Modem', sometimes 'EIA', but they've all been fine once you figure out--generally by Googling for the manual--how to change the configuration, either via DIP switches or some magic combination of keys on the keyboard.) As has been noted, you'll need also a PC for uploading/downloading new virtual disks to/from the Altair. I keep an old PC with a regular serial port handy for this rather than a modern one as I've repeatedly failed to get USB>serial adapters to work.

I strongly recommend not altering the Altair front-panel to help you stick with hexadecimal but instead getting your head around octal. I was in the same position as you in having never used octal before and it's really rather neat once you're used to it as the relationship to binary is based on just remembering the values for patterns of 3 bits at a time (0-0-0 to 1-1-1). Also, it's just good for the brain to get comfortable with new number bases, since they're all just arbitrary conventions. And as I think has been pointed out, you can be a whiz with chmod settings in Unix/Linux once you're octal-comfortable.

Good luck -- it's a very exciting journey, I've found!
mail@gabrielegan.com
 
Posts: 94
Joined: October 11th, 2014, 8:12 am

Re: Sanity check for setup

Postby Semolina » August 13th, 2015, 4:04 pm

Super encouraging! Thanks for your advice!
Semolina
 
Posts: 4
Joined: August 11th, 2015, 9:46 pm

Re: Sanity check for setup

Postby waltermixxx » August 14th, 2015, 8:44 pm

I think you will get a great feel for it by watching all the Video's that Mike has posted on youtube. They really give you a feel for the experience you are about to undertake... It was a major influence in my decision to purchase yet another Altair type computer... I had originally bought a Briel Altair 8800micro but it did not have the same look and feel that the clone has. A much more authentic feel. :) I did not think i would care, but I did. I love the 8800micro, it and all of Briel's creations are great. But this Altair 8800 clone is awesome. You may never have a cooler piece of retro computing. :) (unless you can get a hold of an actual authentic RCA Cosmac VIP single board computer.... (That's a personal thing...) :)

I think you will find everyone was and still is very excited about their Altair Clone 8800...

Cheers. :)
Altair Clone, Briel 8800micro, Replica 1plus (wire wrapped), Cosmac Elf 2K.
I love this stuff, just wish my wife did... :)
waltermixxx
 
Posts: 16
Joined: May 28th, 2015, 1:12 pm
Location: Toronto


Return to General Discussions

Who is online

Users browsing this forum: No registered users and 1 guest

cron