[ltp] T43 and S/PDIF audio output

[Dave Woodfall]

Hi Richard, and thanks for the link and info.

There may be other advantages to using a dock, so I'll have a read up
on those and the port replicators that are also mentioned.

I do have a Behringer USB interface, but my understanding is that USB
interfaces are limited in bandwidth compared to coax or optical,
which is why I wondered if this `AC-link' would be useful.

Cheers,

Dave

On 19/11/20 13:11,
Richard Neill <rn214 at richardneill.org> put forth the proposition:
> Hi Dave,
> I think you'd find a digital audio output on a docking station
> http://www.thinkwiki.org/wiki/ThinkPad_Dock_II
> Otherwise, I recommend the Behringer UCA202 which is a £25 USB audio
> interface. I've used a number of these, either for the optical or analog
> audio out,  This solution is nearly perfect in terms of eliminating
> interference from the CPU and ground-loop hum.
> Aside: I have noticed on one very old amplifier (1970's vintage) that you
> can get squeaks - this arises from the combination of a high-frequency DAC
> and an amplifier with too high a bandwidth, combined with aliasing. This is
> a rare issue though.
> HTH,
> Richard
> On 19/11/2020 11:01, Dave Woodfall wrote:
> > Hello all,
> >
> > I've been looking to see if I can get digital audio output from my
> > T43, so that I can run jackd and connect it to my HiFi DAC.  At the
> > moment I'm doing it from a desktop PC, which I would like to
> > semi-retire.
> >
> > According to modinfo snd_intel8x0 there is:
> >
> > parm: spdif_aclink:S/PDIF over AC-link. (int)
> >
> > What exactly is this AC-link?
> >
> > The only audio sockets are the headphone and mic jacks.  Does anyone
> > know how to capture (hopefully coax) S/PDIF output?
> >
> > In addition, I have a free PCMCIA slot, 2 USB, PS/2 socket, RJ11
> > modem socket, RJ45 NIC socket, parallel port, and external monitor
> > output.  I do have a USB S/PDIF adaptor, but IIRC it is limited
> > quality compared to coax.
> >
> > More info:
> >
> > Alsamixer does show any controls for S/PDIF out, but it does have an
> > extra console driver, which I've not yet found a use for:
> >
> > Card: ThinkPad Console Audio Control
> > Chip: ThinkPad EC 1YHT29WW-1.06
> >
> > Some lspci output:
> >
> > 00:1e.2 Multimedia audio controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family)
> >          Subsystem: IBM 82801FB/FBM/FR/FW/FRW (ICH6 Family) AC'97 Audio Controller
> >          Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR
> >          Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort-
> >          Latency: 0
> >          Interrupt: pin A routed to IRQ 22
> >          Region 0: I/O ports at 1c00 [size=256]
> >          Region 1: I/O ports at 1880 [size=64]
> >          Region 2: Memory at b0000800 (32-bit, non-prefetchable) [size=512]
> >          Region 3: Memory at b0000400 (32-bit, non-prefetchable) [size=256]
> >          Capabilities: [50] Power Management version 2
> >                  Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0+,D1-,D2-,D3hot+,D3cold
> >                  Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
> >          Kernel driver in use: snd_intel8x0
> >          Kernel modules: snd_intel8x0
> >
> > It also lists the modem which has a standard RJ11 socket.
> >
> > Thanks for any info.
> >
> > --
> > Dave
> >
> > Love is a snowmobile racing across the tundra and then suddenly it flips over,
> > pinning you underneath.  At night, the ice weasels come.
> > 	 --Friedrich Nietzsche
> >
> --
> The linux-thinkpad mailing list home page is at:
> http://mailman.linux-thinkpad.org/mailman/listinfo/linux-thinkpad

--
Dave

Love is a snowmobile racing across the tundra and then suddenly it flips over,
pinning you underneath.  At night, the ice weasels come.
	 --Friedrich Nietzsche