[Asterisk-Users] Why does bristuff generate PRI errors for a BRI only server

[Remco Barende]

I am using bristuff with an HFC-S card.

On an incoming call I get these weird PRI errors however, even though 
there is no PRI card in the box nor did I load any PRI modules?

These are the errors:
Jan 20 01:34:22 WARNING[2756]: chan_zap.c:7407 zt_pri_error: PRI: !! Got 
I-frame while link state 0
Jan 20 01:34:23 WARNING[2756]: chan_zap.c:7407 zt_pri_error: PRI: !! 
Received short unnumbered frame
Jan 20 01:34:25 WARNING[2756]: chan_zap.c:7407 zt_pri_error: PRI: !! Got 
I-frame while link state 0
Jan 20 01:34:26 WARNING[2756]: chan_zap.c:7407 zt_pri_error: PRI: !! 
Received short unnumbered frame
Jan 20 01:34:32 WARNING[2756]: chan_zap.c:7407 zt_pri_error: PRI: !! 
Received short unnumbered frame
Jan 20 01:34:37 WARNING[2756]: chan_zap.c:7407 zt_pri_error: PRI: !! 
Received short unnumbered frame

Thanks!