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Offline darkageTopic starter

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Max baud rate for analog modem
« on: January 10, 2010, 07:23:38 AM »
Hi All,

I just pulled out my old USR Courier 56k v.everything X2 Modem! haha such a beast! claimed to be the worlds first software upgradable modem.  I first had it @ 21k6  or 19k2 speed (I think) then upgraded it to 28k8 then 33k6 then 56k via software flashes.

Now just thinking back I remember on older pc's like my 386 and ami 500 that the serial ports couldnt handle above 28k8 I think.   On the PC you had to have a 16550 UART serial port.  

Does anyone know the max achievable baud rate with an analog modem on a  A500 & A1200.

Just wanted to get better understanding of the technical issues that I had back then and if it really was possible B-)
 

Offline darkageTopic starter

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Re: Max baud rate for analog modem
« Reply #1 on: January 10, 2010, 11:06:34 AM »
Quote from: whiteb;537451
Well, on a stock A500, you were limited by the CPU, and the serial.device (Driver), if you used the Commodore supplied Device, then you could not go over 19200 (From memory) without getting errors.  But then you had replacement drivers that gave more speed for the basic CPU. (Like Baudbandit.device). I personally had A500 to A500 at 56k, but I am pretty sure there were devices that ran at 115k on a stock A500.


Whao so it was all dependant on CPU power.  Back then I kept on relating it to UART FIFO.
haha I remember Baudbandit.device and tried it, but hmm kept on getting drop outs.  Come to think of it yes my Ami was unstable above 19k2.  Hey coime to think of it what happened to my old Dick Smith Spirit 2 modem,  that was a bucket of poo hence the reason I spent $600 AUD on the utlimate  USR at the time.

Im  happy to know my AMI can achieve high baud rates,  just needs a accelerator card :P  have to try it one day if Im lucky enough to come across a cheapo one.


Quote from: Jiffy;537460
Serial is as obsolete as my C64, C128, SX64, A1200, A2000, A3000, Mac IIci, Power Mac G3, Archimedes 310, Sun Ultra 2 and some other oldies I have.

Just because it's obsolete, doesn't mean it's not usefull anymore. Hell, we're at Amiga.org here, which is devoted to fully obsolete computers. :-)


Amen!  Im still learning things from my Ami but more for hardware design prespective.  

haha I got a SGI O2 and SUN LX (Lunchbox)  just coz I could and they were cheap back when ppl started to give them up.   back in the day I looked up to SGI/SUN machines as if they were the holy grail.    I probably thought that way since I was learning *nix in general back then.
 

Offline darkageTopic starter

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Re: Max baud rate for analog modem
« Reply #2 on: January 10, 2010, 03:52:14 PM »
Quote from: itix;537505
With some terminal programs you can use Amiga serial port directly and get better performance out of it. I used JRComm regularly at 56kbps on my A500 and I think I even used 115kbps but it slowed down pretty much everything.


I used JRCom as well but still had issues. hmm probably wasnt a good idea to use a telephone extension cord at the time perhaps as well :)

JRCom was pretty cool term proggy, but I ended up using the PC 386 then 486 at the time due to it actually having a hard drive and I could tag files.

Then I would use a null modem to x/fer from pc to ami.  (:  haha when I got a 2nd floppy drive for my Ami it was like a different world.  I could finally decompress DMS archieves :)
 

Offline darkageTopic starter

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Re: Max baud rate for analog modem
« Reply #3 on: January 11, 2010, 05:19:27 AM »
Also from memory AT&V to view the factory default string profiles :)

Remember tweaking the string profiles so much to decrease number of drops out etc.  Always hunting for that perfect string.