NULLMODEM mode

[jdryyz]

I gave this a try for the first time yesterday.

I paired a WiModem232 attached to an Amiga running "TERM". The other computer was a C64 with WiModem (set to 9600baud) running Novaterm9.6c. Both modems have the latest firmware (v6.20).

I successfully transferred a .d64 image over Xmodem without errors, although the file size does call for some patience. Even knowing where my expectations should be, I still thought "couldn't this be faster?" 

I did the same test with ZModem (just for giggles) but I saw familiar errors on the C64 side. I don't know of any scenario where Novaterm's Zmodem has ever worked error free...unless in a rare case where I used it over an analog modem in that past. My memory is hazy on that. I should note that I tested it using both a .d81 image and REU as the download drive.

Having tested the nullmodem option to my satisfaction, I powered off my C64 and turned it back on. I noticed the WiModem was taking longer than usual to find my router. It came back saying no router found! Hmm...I *did* remember to add the "0" after the command so it would be temporary. Could it have placed it in permanent mode instead?

Here is my exact typing of the command:

at*nullmodem0

I then power cycled the WiModem232 and the same thing happened. It failed to find my modem. I also noted at this point that the OLED status showed "no wifi".

Okay, so let's see if I can simply reconnect it to my SSID. Yep, that worked. Did a test BBS connection. Good there also.

So, did I not issue the command correctly or is the modem going into permanent mode regardless of the added 0?

[admin]

Once you have entered into NULLMODEM mode, the WiFi settings are turned off so you will have to re-connect with your router. This is done because in NULLMODEM mode the modem does not use the router at all.

So, just go reconnect each WiModem back to your router.

Novaterm's handshaking is backwards. You have to disable hardware handshaking in order to have it enabled.

[jdryyz]

Ahhh...okay. I thought the temporary setting would automatically restore it back to its default mode, including the router connection.

I vaguely recall the Novaterm handshaking setting. I thought that it was reversed in a specific version of Novaterm but was corrected later. I may also be thinking about the Striketerm variant.

Incidentally, I am using Novaterm 9.6c.

[admin]

The temporary (0) setting prevents the WiModem232 from re-booting directly into NULLMODEM mode. If you set it to 1 then the WiModem232 will always boot into NULLMODEM mode.

Novaterm 9.6 has the problem. Striketerm fixed this issue.

[jdryyz]

The temporary (0) setting prevents the WiModem232 from re-booting directly into NULLMODEM mode.  If you set it to 1 then the WiModem232 will always boot into NULLMODEM mode.

Understood on that.

I was thinking this could work out to be a feature request. With the temporary setting, could it also reconnect automatically to the last used SSID after a power cycle?

[admin]

The WiModem232 Pro should do this already - it does on mine. The original WiModem and WiModem232 do not. This has something to do with the WiFi stack that is built into the RF module.

I just noticed that you put this thread under the WiModem232 Pro category. Is that what you are using?

[jdryyz]

The WiModem232 Pro should do this already - it does on mine.  The original WiModem and WiModem232 do not.  This has something to do with the WiFi stack that is built into the RF module.

In this case I am using an original WiModem232 and WiModem. I also recently acquired the WiModem232Pro but have not tested NULLMODEM on that one. It has been moved over to another computer that has an incomplete system. I do plan on testing the new one more in the near future.

I just noticed that you put this thread under the WiModem232 Pro category.  Is that what you are using?

I thought it I posted it in the category for both the original and the Pro version (WiModem232 / WiModem232 Pro).

[jdryyz]

This may be a silly question. I did check the manual first.

When two modems are paired this way, does the port speed need to match? I had no problem pairing my 38.4Kbps WiModem232 and WiModem connected at 9600 but, despite everything on the terminal side having the correct/suggested settings, I still immediately got errors during ZModem transfers. 

I tried two different terminal programs on the Amiga side, finally settling on NComm. At this time I also realized it would be good idea to match the block size to what is set in StrikeTerm (1024 blocks). Amiga terms typically default to 16k for ZModem. This change was perhaps a Duh! moment. I've never given much thought to it in the past.

I had trouble selecting NComm's built-in Zmodem (it causes a GURU) so I stuck with the external xprz.library. I then set the port speed to 9600 and reestablished NULLMODEM mode.

Finally...I am able to start my upload...but...sigh...still errors.

I then thought...what the heck, let's try changing StrikeTerm's handshaking setting from software back to hardware.

Another transfer was started......hey....no errors!  It would seem the hardware handshaking setting *is* correct in StrikeTerm.

Uhh oh.....the transfer made it to approx 60% completed and then I started to see errors on the C64 side.    Well, this is still good. A first for me, actually. I have never seen a ZModem transfer on a C64 go this long without errors.

I will keep testing....

[admin]

The port speeds need to match if you are using a protocol that relies on timing, like Zmodem.

[jdryyz]

Okay, for reasons unknown, I was able to complete a full .d64 image transfer from my Amiga to the C64 using the same conditions that previously resulted in errors. I guess it would now be useful to know how many times I can repeat this. The contents of the image look good. I just need to test it.

I'm still a bit disappointed by the transfer speed (thought the ZModem stream would go by a bit faster) but this might be the best the C64 side can do with this setup. StrikeTerm is using the REU as the download drive.