DIY RS232 WiFi Modem for under $10

[TMA-1]

Does your TI-99/4A have a serial port, either in the PEB toaster oven or perhaps a NanoPEB?

 

Got another favorite retro-computer with a standard RS232?

 

Got 10 bucks or less, and about an hour's time, all-in?

 

Many Bulletin Board Systems from the past have been resurrected on the modern Internet via Telnet.  A list is <here>.

 

"WiFi Modems" (actually modem emulators) exist that behave like the Hayes Smartmodems of old.  These devices use your own existing household WiFi to connect your retro-computer transparently to the Internet, Telnet to the BBS, and hand your treasured retro the traffic at a baud rate you remember from old.

 

The Commodore people have been surfing BBS's like the Old Days for some time now.  It's about time the rest of us caught up, and beat them soundly in the cost department.

 

This document below has been foreshadowed in the following threads:

• Telco DSSD <here>;
• Quest for Terminal Software that Works with the Quirky NanoPEB Serial Port <here>; and,
• Telco patch for NanoPEB v1 Serial <here>.

 

Here it is.

 

TMA-1's RS232 WiFi Modem Instructions.docx

Edited December 30, 2019 by TMA-1

[+OLD CS1]

Nice write-up.  And it cleared both local anti-virus scan and VirusTotal.

 

From https://nurdspace.nl/ESP8266

Quote

802.11 b / g / n

Still not 5GHz...

[Ed in SoDak]

19 downloads already.

For someone like myself with no Telnet experience Ian's doc file was pretty easy to digest. If the install is as smooth, I'll update shortly after the goodies arrive and I get 'em all connected.

-Ed

[TMA-1]

Slight update to the document:  It has come to my attention that there are more than one Chinese factory churning out these ESP8266 prototyping "breakout" boards.  Some are CP2102 and some are CH340, referring to the USB interface chip used.  Either will work fine, but they require different drivers.  The instructions have been updated accordingly to source either flavor.

TMA-1's RS232 WiFi Modem Instructions.docx

[Ed in SoDak]

Care package received from Ian TMA-1! After a couple days ironing out wifi security protocols (WEP vs WPA et al) I'm in! I'm right now on Heatwave reading all the posts. On a stock TI99/4A with PEB no less. Wifi on the TI with only this dinky card to pull it off, whoda thunk it? I'm totally blown away, thanks so much for the experience!

 

Doing same on my various Macs is also no problem and hate to say it, but perhaps more convenient, since reading a scrolling post in 40 columns often requires I call up Review Log in Telco to actually see/read it. Way back when, I could read almost as quick as my 2400-baud modem could scroll. Even at 2400, this ESP module seems faster. Zterm on the Mac would allow 80 columns and a smoother log review.

 

Reminds me that back in the '90s I would log the whole session to the printer for a quick review and/or to disk and read it afterwards at my leisure or copy off the salient stuff. After all, for quite awhile I was paying through the nose for connect time. That would make me want to get on, grab it all and get back off quick. Though I jumped on it when Delphi finally offered Unlimited Connect Time for only $20 a month. I caught heck from the wife for that $120 connect bill one month before they provided that. whoops!

 

I'll post up some of the nitty gritty details next day or so. It wasn't as smooth as we hoped, but now that I've plowed the road, I can relate some pitfalls I encountered that others will be able to avoid and head straight to the goodness of Telnet. For now, I will relate the main issue was my death-grip on my old Macs. I refuse to relinquish my favorite os9 Classic apps, but come to find my primary Mac is too old for 802.11.g. The result being it doesn't support WPA security, which this flavor of ESP requires to access my wifi. We found a way around that, for now, at least by using newer Macs while surfing Telnet on my TI and changing the Wifi back to WEP afterwards. I suspect this is a niche problem and most users won't see it.

 

Meh, while typing all this, Heatwave logged me off for inactivity! Oh, the agony!

 

Before I go, a Big Thanks to Tim for maintaining Heatwave al these years and taking the time to drag up my so-soon-forgotten password so I could experience it on the genuine article!

-Ed

 

 

 

Edited January 27, 2020 by Ed in SoDak

[Ed in SoDak]

It's easy to use Telnet with this little board. For the TI with PEB and standard TI RS232, a 3-wire connection is all that's needed.

 

TI DB25_____ESP DB9

RX  2    _____  2 RX

TX  3    _____  3 TX

Gnd 7   _____  5 Gnd

 

Yes, I have RX to RX and TX to TX. A quirk of how TI set up the serial connector on the RS232 card. I'm just using solder-pin connectors and a ribbon cable, so it's easy to make or modify.

 

I seem to be locked at 2400 baud since I'm unable to edit the setting in the ESP. I believe Ian <TMA-1> used his Arduino to access it from the USB connector side. From a term program over the RS232, typing "AT$SB=96" it goes through the motions, but doesn't change. I simply lose contact with it till I reboot the ESP and change the term prog back to 2400. Oh well, 2400 is plenty fast to read or send messages, which is all I've done so far.

 

And as noted in my prior post, the wifi itself must be set to WPA or WPA2 security. Myself, I use WEP, so must change the wifi before using the ESP board. All I got onscreen otherwise was "Error." Though I could call up the ESP's default list, I could not connect to Telnet. Hope this saves some grief for someone who uses WEP as I do.

Here's a pic of my TI setup. Too bad I accidentally cropped out the ESP board! It's getting power from my Mac over USB. I'm using an unmodified copy of Telco set to 2400 8N1.

Not real convenient at the moment. The console is sitting sideways to the old, blurry TV and PEB on the floor in "tower" mode. I'm mostly using it to port my floppy collection over to emulation as I find the time and inclination. Typing messages right now is strictly hunt and peck. If I start using Telnet more, I'll rearrange things or just use the Mac to connect. Blasphemy!

 

Another couple pics show how I connect it to the Mac. I have Keyspan's Mac DB8 serial to USB adapter and an old Mac modem cable. Connect power to the mini-USB port the Keyspan to the Mac also via USB. The keyspan driver is a simple install, with a program to choose which of two ports to use. Set your term program to match the port, and connect at 2400 8N1.

And there you have it! Cheap and pretty easy way to get on Telnet! Maybe Ian will add how he's able to edit the ESP's defaults.

-Ed

 

 

 

 

Edited February 2, 2020 by Ed in SoDak

[Ed in SoDak]

You can do a lot more with one of these ESP8266 flavors. The one I have seems to be the ESP12E which breaks out the ESP8266's pins on a larger board for easy access, plus adds quite a bit of support hardware. The software can be up to the individual user and their comfort/experience level.

 

Mine has some features "hidden" or beyond my understanding on how to access the flash memory. All I can find on my board is "modem" software. Reflashing with new or edited software uses simple tools on PC, Intel Mac, Linux or Arduino. What to reflash it with is the question.

 

A good jumping off point to learn more about 'em is here: https://1200baud.wordpress.com/2017/03/04/build-your-own-9600-baud-c64-wifi-modem-for-20/

 

It seems like the one featured there for Commodore is very similar to mine. It's a whole 'nother world I've never dabbled in, but have been curious. The Internet of Things....

-Ed

[Ed in SoDak]

Eureka! I revisited the link I posted just above and solved my 2400 baud limit. All we needed to add were these two commands: at&p0 and at&k1 after which we can type at$sb=96 to set it for 9600, higher is also possible.  Next change your term program to match and bingo! I can now test 9600 and see what my TI's limit is above that.

 

Edit: It's even easier. The internal listing has an error. Instead of typing at$sb=96 as it says to do, I "accidentally" typed "9600" and was surprised it worked. Tried that again, typing "at$sb=19200" and was able to connect.

 

at?

WIFI SIXFOUR BUILD 20160621182048 BY @PAULRICKARDS
BASED ON GITHUB.COM/JSALIN/ESP8266_MODEM
AT COMMAND SUMMARY:
DIAL HOST.....: ATDTHOST:PORT
SPEED DIAL....: ATDSN (N=0-9)
SET SPEED DIAL: AT&ZN=HOST:PORT (N=0-9)
HANDLE TELNET.: ATNETN (N=0,1)
PET MCTERM TR.: ATPETN (N=0,1)
NETWORK INFO..: ATI
HTTP GET......: ATGET<URL>
AUTO ANSWER...: ATS0=N (N=0,1)
SET BUSY MSG..: AT$BM=YOUR BUSY MESSAGE
LOAD NVRAM....: ATZ
SAVE TO NVRAM.: AT&W
SHOW SETTINGS.: AT&V
FACT. DEFAULTS: AT&F
PIN POLARITY..: AT&PN (N=0/INV,1/NORM)
ECHO OFF/ON...: ATE0 / ATE1
VERBOSE OFF/ON: ATV0 / ATV1
SET SSID......: AT$SSID=WIFISSID
SET PASSWORD..: AT$PASS=WIFIPASSWORD
SET BAUD RATE.: AT$SB=N (3,12,24,48,96 >>> Wrong. Type the actual commect speed, i.e. 9600.
                192,384,576,1152)*100
FLOW CONTROL..: AT&KN (N=0/N,1/HW,2/SW)
WIFI OFF/ON...: ATC0 / ATC1
HANGUP........: ATH
ENTER CMD MODE: +++
EXIT CMD MODE.: ATO
QUERY MOST COMMANDS FOLLOWED BY '?'

OK

 

Another link for those wishing to delve deeper: https://www.esp8266.com

-Ed

Edited February 2, 2020 by Ed in SoDak

[+arcadeshopper]

depending on the terminal program you will have different experiences

TIMXT can do 19200

TELCO/MXT starts dropping chars after 2400

fastterm can do 9600 usually.. but may need some xonxoff

[Ed in SoDak]

See my edit above. I was typing it wrong, just like they told me too! Once I figured out you just enter the new baud rate fully, i.e., 9600 instead of just 96, it's easy to change. My TI has done 19.2 pretty reliably. I have the ESP set for that now on my Mac. The ESP is supposedly set to 115,200 at the factory. This module was defaulted to only 300, but Ian upgraded it to 2400 when he built it and shipped it to me.

 

BTW, that made my experiments plug 'n' play for the most part, with just a couple obscure gotchas to make it interesting.

-Ed

[TMA-1]

Ed has gone above and beyond in exploring the capabilities of these intriguing little Arduino-like ESP8266 devices!  Thank-you Ed.  You've taught me a thing or two about them.

 

The modem emulator document I posted is, I hope, less confusing because it skips all the extra-curriculars.  It is designed to get you online as quickly and simply as possible.

 

When Ed refers to the "internal listing", he is referencing the commands help available by typing "at?".  It is quite misleading just as he describes.

 

I blame myself for pre-setting the baud rate to 2400 on the unit I sent my old friend.  If he had been forced through all of my document, he would have seen the command for this firmware is "at$sb=9600" or the like.  It does not require the Arduino SDK to change.

 

Thank-you arcadeshopper for the info on teminal programs.  I was using Telco and found it dropping characters after 2400 just as you say.  I thought it might be a limit of the TI-99/4A; glad to know it's not.

 

In my case, I have a NanoPEB, which has required terminal software "adjusted" (hacked) by InsaneMultitasker to work with it's quirky RS232.  A modified Telco is the one that works for me, so I may be stuck at 2400.  That's okay, it even emulates the speed I had experienced back in the day, lol.

 

I'd be happy to see feedback from others who build and try this little toy, but perhaps everyone who downloaded the document is waiting for parts from China?  ?

 

[Omega-TI]

8 minutes ago, TMA-1 said:

...it even emulates the speed I had experienced back in the day...

Now that's salesmanship of the first order! ?