[RFC] Keeping send-delay for all RS232 ttys only?

[Aleksander Morgado]

Hey Giacinto,

> 100ms between characters seems excessive.
> In general there are the RTS/CTS on the serial line and on the virtual
> serial over usb (supported by option and acm drivers) for this.
> A stripped down RS232 with only TX/RX/GND could need some delay, but
> it is very difficult to guess how much: in this case it would be
> better to have it as a parameter.
>

Allowing to change it with udev tags seems an option, while keeping
the same default value for old RS232 modems.

> Some modems require a different delay: between the last answer and the
> following command, to have time to output some URCs in between.
> At least for Cinterion modems, they don't output URCs between a
> command and its response, so they must be given a chance.
> The Cinterion ATC guides always specify 100ms, but it turns out that
> 1-2ms are enough.
>

Please note that the send-delay is not the timeout in between AT
commands; it's the timeout in between the characters of a given AT
command; i.e. if running AT+GCAP?:
"A" then 100ms, "T", then100ms, "+" then 100ms, "G" then 100ms ....

-- 
Aleksander
https://aleksander.es