On Nov 07, Léo Serre <leo@lstronic.com> wrote:

>     'OK' 'AT+CFUN=1,1'
This means "sending +CFUN after the OK prompt", but there is nothing 
before that which tells the modem to output the OK prompt.

I think that you can just use +CFUN in the normal connect script, like 
this one that I wrote for Debian ages ago:
https://anonscm.debian.org/git/collab-maint/pkg-ppp.git/tree/debian/extra/chatscripts/gprs

>  2. Is there an other way to send an AT command while pppd is running (or
> none)?
No.

-- 
ciao,
Marco