Avvio 792 4.2.2 Jelly Bean - ring time too short Very new at Android, sincere apologies if asking incorrectly, just joined.

Ring time for incoming calls is only 15 seconds.  Just enough time to go to voice mail by the time I dig phone out of backpack or break my neck running to get it, let alone find it.

Can apparently only be reset in 5 second increments up to 30 seconds by dialing 61*local provider voicemail code30#.  

Service provider is Claro in Colombia.  Appears to be due to no MMS available.  Is this due to phone itself, or due to local service provider? 

Can this be reset on the device itself?  Is there anything in the code that can be modified?   

Thanks!
Can this be reset on the device itself? Is there anything in the code that can be modified? 


It is possible to extend the ring time, but you have to deactivate voice mail and call forwarding/divert for no answer (i.e. missed call).


  Is this due to phone itself, or due to local service provider? 


I found that Claro Colombia is one of GSM network provider. It seems there is a "standard" for GSM network to have 30 second divert 'rule'1. Most telcos will follow such rule, although some may ignore it. From Wikipedia,


  In some networks there may be a limit of not more than 30 seconds before forwarding (i.e. "XX" can only be 5, 10, 15, 20, 25 or 30; all greater values, like 45 and 60, will result in the forwarding command being rejected and an error message returned).


Without voice mail and call forwarding/divert, the limitation will be gone, although most telcos still only allow ring time up to 40~60 seconds.

The most direct solution is to contact their service and ask if it's possible to extend the ring time before the call is diverted. A friendly suggestion is to put the phone at easier-to-reach place. Worse, you might need to find another provider that is suitable for you (off-topic here).

1 Based on research on many forums/articles such as this, though there is no legit reference.