PCB layout of WiFiModem

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PCB layout of WiFiModem

I made my own PCB Layout of the WiFi Modem.  It has DB-9 female and DB-25 male serial connectors, line level shifters, jumpers for null modem settings, RTS/CTS support, and the support to flash the ESP12E on board. 

 

https://github.com/profdc9/WifiModem

 

It should be relatively easy to assemble.

 

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Easy enough it seems. What

Easy enough it seems.

 

What WiFi modem firmware are you going to run on the ESP32?

 

 

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I've looked at several, but
I've looked at several, but this one seems like the winner:

https://github.com/stardot/esp8266_modem/wiki

It implements RTS/CTS and uses a jumper (which I have since added to the design) to select if hardware flow control is used.

Dan

 

 

 

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Apples generally don't use

Apples generally don't use hardware flow control.  At least not RTS / CTS.

The Super Serial card can run 9600 baud all day long without hardware flow control.  So can the IIc with its hamstrung serial port (that lacks hardware flow control) and the IIc+ / IIGS and Macs.

 

Anyway, to make outgoing "calls" that firmware on the github page will work, but it doesn not have a faithful Hayes command set.

Neither does the other dominant wifi modem firmware out there - Bo Zimmerman's zimodem.

 

To receive calls automatically (as if you're running a BBS) reliably most software wants the modem to have a funcitonal DSR signal, and the above two firmwares don't do DSR properly.  The only WiFi modem out in the ether today that does do DSR properly is cbmstuff.com's Wimoreem232 but that project is a commercial closed-source project, and the firmware is not available.

To make outgoing calls, even a $2 ESP12 chip with its 8 i/o pins can work perfectly.

 

 

 

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Are you sure about this?  I

Are you sure about this?  I used to have a Courier HST (which does 9600/14.4k baud) and an Apple ][e with ProTERM and I remember it requiring RTS/CTS to work.  Also, for running a BBS, a modified cable was required bridging DCD to DSR.  I had this working as well.

 

 

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profdc9 wrote:Are you sure
profdc9 wrote:

Are you sure about this?  I used to have a Courier HST (which does 9600/14.4k baud) and an Apple ][e with ProTERM and I remember it requiring RTS/CTS to work.  Also, for running a BBS, a modified cable was required bridging DCD to DSR.  I had this working as well.

 

 

That modem came out waaaaay after the Apple II era.  I'm surprised ProTERM really would even work very well with that modem.  ProTERM was one of the later packages though, and if any supported faster modems, that would have probably been the one.

 

BBS sofrware was always pretty picky about modem cabling.  Most BBS software for example wouldn't work on a //c because the 5 pin serial port didn't have DCD, CTS or RTS.  Those signals were available on the motherboard.  I knew someone who found the spots on the motherboard and ran wires out through the vent slots on his //c to a DB25 adapter.

 

 

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From the GBBS Pro manualhttps

From the GBBS Pro manual

https://mirrors.apple2.org.za/ftp.apple.asimov.net/images/communications/bbs/gbbs/GBBS_II_Manual_1.7.pdf

this is what the pinout is for connection to a MODEM

 

 

PINS APPLE (DB25)PINS MODEM (DB25)
2(TD),3(RD),4(RTS),5(CTS),7(GND)2(TD),3(RD),4(RTS),5(CTS),7(GND)
6(DSR)

12(DCD2)

8(DCD),20(DTR)8(DCD), 20(DTR)

 

Another from this page is (https://www.geneb.org/tcpser/tcpser-how.pdf ):

 

PINS APPLE (DB25)PINS MODEM (DB25)
2(TD),3(RD),4(RTS),5(CTS),7(GND)2(TD),3(RD),4(RTS),5(CTS),7(GND)
6(DSR)

8(DCD)

8(DCD) and 20(DTR)20(DTR)

 

Another from this page is (https://www.geneb.org/tcpser/tcpser-how.pdf ):

 

PINS (DB9 Raspberry PI with USB Serial Adapter)PINS APPLE II (DB25)
8(CTS),7(RTS)4(RTS),5(CTS)
3(TXD),2(RXD)3(RXD),2(TXD)
4(DTR)8(DCD)
1(DCD)20(DTR)
5(GND)7(GND)
  

 

So I think the GBBS Pro BBS software expects to get the DCD signal from the modem through the DSR signal. 

 

The latest version of the board actually lets through the DCD and DSR signals, so the firmware could be reconfigured to change the DCD to redirect to DSR.

 

 

 

 

 

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