asterisk users - Jul 2006 - PRI channels filling up

Hi All

I have an Asterisk box with 2 PRI's going into a Samsung DCS 500.  After 
a day or so of usage, the PRI channels are all used up and users cannot 
make or receive calls over the PRI's.  I get many of the following 
messages in the logs:

    Ring requested on channel 0/1 already in use on span 1.  Hanging up 
owner.

zapata.conf


[channels]
    context=samsung
    switchtype=unknown
    pridialplan=unknown
    echocancel=yes
    echotraining=800
    echocancelwhenbridged=yes
    rxgain=1
    txgain=-1
    callerid=asreceived
    musiconhold=default

    signalling=pri_net
    group=1
    channel => 1-15,17-31,32-46,48-62


I have since changed the switchtype to QSIG and the Samsung is now set 
up with QSIG.

Kind Regards
Garth