[Discuss-gnuradio] bytes lost after mpsk-receiver

[thawdar]

Hi all,
I've been learning gnu-radio for two-months now.GNURadio mailing-list archives have been a lot useful to me and now I have a question or two to ask.
When I ran the example benchmark_loopback.py, every parameters with default-setting, it was fine and  I have received 666 packets correctly.
However, when I changed the code so that I'm reading the (pseudo-random) data from a file (12500 bytes total) and packet-size of 100bytes, I found that I didn't receive the last packet.
Another thing I changed to the code is that to write the data retreived from the receive side to a file. I defined an outfile and in rx_callback funcition, I wrote payload data to the file and looked at the retreived data and confirmed that I'm shot of the last packet. 
I also logged data at various stages for troubleshooting and I found that I'm getting 16bytes less than what I should after the mpsk_receiver (which I think leads to the last packet loss at the correlator later?)  I was using the default parameters for the receiver; I tried to study on the workings of it, and tweaked a few parameters but in vain.
Any pointers will be much appreciated.
(I also checked the queue watcher thread to see how many times rx-callback is called and it is also one less than it should be.)

Another question I have is on the default_access_code used in the packet_utils.py. I read somewhere in the mailing list that it has to do with GSM systems. Can anyone tell me if this access_code is from some IEEE standard and if so, which one?

Thanks in advance.

NT