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Re: WiModem - Very good article about [message #367012 is a reply to message #366509] |
Sat, 28 April 2018 10:04 |
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Originally posted by: Henry Pedro
On Friday, April 20, 2018 at 1:54:05 AM UTC-3, 6502en...@gmail.com wrote:
> https://vintagegeek.wordpress.com
Great little device the Wimodem232.
One of the things about ProTerm, though (and the SSC / Iic / IIGS modem port) is that you cannot receive any data into the computer unless there is a high signal at the Carrier Detect pin (or the Handshake-In pin on the Iic).
There are a couple of ways around this.
First is to keep the CD signal on all the time - the WiModem's CD signal is inverted, so you first have to correct the polarity with AT*D1. Then turn CD on all the time with AT&C0.
The advantage is that you'll always see what you're typing to the WiModem and you'll always see the WiModem's responses. The drawback is that ProTerm cannot sense a remote hangup.
The other way to do it is to modify your serial cable to connect the computer's CD pin to the modem's DSR pin and turn the DSR switching feature on, and DTR hangup feature on with:
AT&S2D2.
This way when you cycle DTR, the Wimodem forces a hangup and turns DSR low. When DTR goes high again (ProTerm does this automatically when you use the Hangup command) it brings DSR high.
The advantage here is that you can see what you're sending the modem when you type commands in and see the modem's responses. You also enable ProTerm to detect a remote hangup because the WiModem will turn DSR low and ProTerm will see this as a hangup, and return to "offline" mode.
The only drawback is that you have to physically make ProTerm hangup with the hangup command to cycle DSR high again.
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