unable to trace B channel

[Christoph Hoenig]

Hi,

I installed 5.3-release in order to trace the b channel with isdntrace 
in analyze mode. Unfortunately I was only able to trace the incoming and 
outgoing D channel data.

# isdntrace -a -b -d -B

Althoug I supplied the necessary -b switch no B Channel data is 
recorded. When turning off the D channel trace like in the command above 
(-d), the size of the binary dump is always 0Kb. With the documentation 
in mind I thought something was wrong about the i4brbch device. But at 
boot time everything seems to work quite well:

kernel: isic0: [GIANT-LOCKED]
kernel: isic0 at port 
0xb00-0xb1f,0x300-0x31f,0x1300-0x131f,0xee0-0xeff,0x6e0-0x6ff,0x16e0-0x16ff,0x1b00-0x1b1f 
irq 10 flags 0x4 on isa0
kernel: isic0: passive stack unit 0
kernel: isic0: AVM A1 or Fritz!Card Classic
kernel: isic1: [GIANT-LOCKED]
kernel: isic1 at port 
0xa40-0xa5f,0x240-0x25f,0x1240-0x125f,0xe20-0xe3f,0x620-0x63f,0x1620-0x163f,0x1a40-0x1a5f 
irq 11 flags 0x4 on isa0
kernel: isic1: passive stack unit 1
kernel: isic1: AVM A1 or Fritz!Card Classic
kernel: i4bipr: 4 IP over raw HDLC ISDN device(s) attached (VJ header 
compression)
kernel: i4bctl: ISDN system control port attached
kernel: i4brbch: 4 raw B channel access device(s) attached
kernel: i4bisppp: 4 ISDN SyncPPP device(s) attached
kernel: i4b: ISDN call control device attached
kernel: i4btel: 4 ISDN telephony interface device(s) attached
kernel: i4btrc: 4 ISDN trace device(s) attached

The irqs used by my 2 non-PnP ISA Cards (AVM Fritz!) are reserved for 
isa slot use in the bios. I also tried to take a look at the debug ouput 
printed to the screen after a `isdndebug -m`. I don't really understand 
the ouput but at least I didn't found anything that looked like an error.
Would be grateful to hear about things I can try, as the i4b doc, FAQ, 
Google and mailinglist archive didn't help on solving my problem.

Christoph