using wvdial or NetworkManager while connecting on a USB 3g phone modem in India (on the Reliance GSM 3g network)

[Tim]

Ranjan Maitra:
>> ATZ
>> -->  Sending: ATQ0

Ron Leach:
> No.  Why has there not been an 'OK' from the ATZ?

>> ATQ0
>> OK

> Well that looks acceptable but, I wonder if perhaps the 'OK' is the 
> 'OK' from the ATZ? 

Butting in here, from my dial-up days as a BBS SysOp, the ATZ reset
modem command could take a while to complete, and any other commands
sent in the meanwhile may be buffered, or simply lost, and were most
likely lost.  It may well be that their phone takes a while to reset,
too.

It used to be necessary to either have scripting that waited for the OK
before proceeding, or simply have a long enough delay before issuing the
next one.  Though it was really best that scripting waits for an OK
after each command before proceeding.

Looking back at the whole original log...

>>  $ sudo wvdial LG
>>  --> WvDial: Internet dialer version 1.61
>>  --> Initializing modem.
>>  --> Sending: ATZ
>>  ATZ
>>  --> Sending: ATQ0
>>  ATQ0
>>  OK
>>  --> Re-Sending: ATZ
>>  ATZ
>>  OK
>>  --> Sending: ATZ
>>  --> Sending: ATQ0
>>  ATQ0
>>  --> Re-Sending: ATZ
>>  ATZ
>>  --> Modem not responding.


The re-sending portions looks like things are getting out of sequence.
And there's little point in sending commands before an ATZ unless they
store something, as they'll be negated by the ATZ.  And, there's not
always a need to do a modem reset, so if the wvdial.conf file allows it,
you could try removing it.  Try just swapping ATZ for just AT, by
itself, as an init string, and see if you get the extra OK response, and
if things proceed any further.

-- 
[tim at localhost ~]$ uname -rsvp
Linux 3.9.10-100.fc17.x86_64 #1 SMP Sun Jul 14 01:31:27 UTC 2013 x86_64

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