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+--- Thread: Apple IIc + Proterm 3.1 (/showthread.php?tid=1248)
Apple IIc + Proterm 3.1 - modemiic - 02-09-2026
Hello all,
I use Proterm 3.1 with my Apple IIc and WiModem232 V2 @ 9600. I use the suggested initialization string and driver:
Generic Fixed Speed (RTS/CTS) driver
Init string: ATX1&C0&K1&S1
Apple //c Serial Port
The cable is this:
1 Handshake Out 20 DTR
2 Data Out 2 TxD
3 Ground 7 Gnd
4 Data In 3 RxD
5 Handshake In 6 DSR
Proterm 3.1 can initialize the modem upon startup successfully.
When I use Proterm's Dial function, Proterm does not recognize that the modem connected. I work around that by going on-line (solid-apple T) and dialing out using ATDS=X, where X is the index of the saved url. Interestingly enough, Proterm 3.1 does dial out if I use the Smartmodem 300 driver.
ZModem downloads start giving errors after the first time the computer saves the file to disk; Proterm reports that it was expecting one type of packet but got another (don't recall the exact packet types now). I need to cancel the download manually and power cycle the modem.
When I don't do a file transfer and use +++ to get the modem's attention, and then ATH to disconnect, I do not receive anything else from the modem. I can see the modem disconnected (through the OLED display), but I get no response from AT commands (although I also do see the modem gets the commands once again through the OLED display).
Any ideas of what could be wrong?
Thanks
Armando
RE: Apple IIc + Proterm 3.1 - admin - 02-10-2026
ProTerm is picky about the driver. There is a driver for the Apple IIc because that cable is different.
Setting &C0 tells the terminal program that the modem is ALWAYS connected (online). This really should be &C1 so that connection state follows the actual connection state (connected to a BBS or not).
For the Apple IIc with your cable you want to use &K0 to disable flow control. DTR/DSR is not a supported mode. If you changes the cable to be normal (using RTS/CTS) then you can use &K1.
&S0 does nothing... it is ignored.
As far as Zmodem protocol is concerned... this is difficult to make work because there are many factors involved due to this being a wireless (WiFi) connection instead of a hard-wired (telephone) line. Zmodem has a critical ACK window that must be met. The speed of your router and ISP all play a part in how fast the ping times are. Too slow and you will get errors. Another reason for errors is using the wrong protocol for the BBS you are calling. If you are calling a "Telnet" based BBS then you need to enable Telnet translation or file transfers (any protocol) will not work.
RE: Apple IIc + Proterm 3.1 - modemiic - 02-11-2026
Thanks for the response. I will change to C1 and K0, and drop S0.
Is there a cable pinout that would work better for the IIc?
Thanks again.
Armando
RE: Apple IIc + Proterm 3.1 - admin - 02-11-2026
So, it looks like for the IIc cable you should have pins 1 and 5 connected together... no RTS/CTS. There is some good cable information here:
https://adtpro.com/connectionsserial.html