On Apr 27, 2009, at 11:00 PM, Jane Chen wrote:

Hi David,

I don't get what you said about the 5110 and 3310. Sorry for my poor knowledge and English.  

No problem.

Did you mean that the SIM holder of 5510 is easily to be broken, so SIM cards cannot be read by the 5110? 

Correct.  The SIM holder on the 5110 is built with small plastic parts that are easily deformed or broken, causing the SIM to lose electrical contact with the phone.  Other than that, I personally like the 5110 very much.  As long as the SIM doesn't fall out of the holder, is it a very good phone.

What did you mean "at a time if your own L3 error handling isn't to spec"? Is L3 of OpenBTS different from spec?

OpenBTS is a work in progress, especially in the area of error-handling.  Sometimes the handset falls into an error state that is not cleared correctly by OpenBTS.  If the handset were perfect, it would clear the error state quickly on it own.  But real handsets are not perfect and some have bugs of their own that can prevent errors from being cleared promptly.  When this happens, the handset can "hang" and be non-responsive for 30-60 seconds, until an internal timer expires and the phone aborts the operation.

Thank you,

David A. Burgess
Kestrel Signal Processing, Inc.