I am preparing for DSL, and have just added a Corning DSL pots splitter
where my service enters the house. The splitter has a Voice and a Data
output. The incoming went to the Network terminals. The existing house
phone wiring went to the Voice, and, from the Data terminals, I ran a
separate phone wire to a jack by my computer. Then, to see its effects,
I plugged in my modem (56k)to that DSL jack.

  Here is where the confusion arises. My computer modem actually
connected to my ISP at a slower speed than before. I did not expect
that result. I tried dialing over and over. When I plugged it back into
the normal (original) phone jack, it returned to its previous 'fast'
speed. Then, to prove my cable run was OK, I reconnected the new DSL
cable also to the Voice terminals at the splitter. Presto - my speed
was back on that DSL jack. Thus, using the Data output caused the slow
down. What will happen when high speed DSL is connected? Any ideas?
Thanks.

nc_flyfisher <ejeltrup@att.net> wrote:
> I am preparing for DSL, and have just added a Corning
> DSL pots splitter where my service enters the house. The
> splitter has a Voice and a Data output. The incoming went
> to the Network terminals. The existing house phone wiring
> went to the Voice, and, from the Data terminals, I ran a
> separate phone wire to a jack by my computer. Then, to see
> its effects, I plugged in my modem (56k)to that DSL jack.

> Here is where the confusion arises. My computer modem
> actually connected to my ISP at a slower speed than
> before. I did not expect that result. I tried dialing over
> and over. When I plugged it back into the normal (original)
> phone jack, it returned to its previous 'fast' speed. Then,
> to prove my cable run was OK, I reconnected the new DSL
> cable also to the Voice terminals at the splitter. Presto -
> my speed was back on that DSL jack. Thus, using the Data
> output caused the slow down. What will happen when high
> speed DSL is connected? Any ideas?  Thanks.

I am not surprised.  Analog (56k) modems are a voice service,
use voice frequencies (0.1-3 kHz) designed to pass through
telco voice channelizations (FDM/digitilization).

DSL uses _much_ higher frequencies (50-1000 kHz).  The taps on
the splitter are set to mostly let the appropriate frequencies
through.

-- Robert

> I am preparing for DSL, and have just added a Corning DSL pots splitter
> where my service enters the house. The splitter has a Voice and a Data
> output. The incoming went to the Network terminals. The existing house
> phone wiring went to the Voice, and, from the Data terminals, I ran a
> separate phone wire to a jack by my computer. Then, to see its effects,
> I plugged in my modem (56k)to that DSL jack.

Uh, don't do that.  A modem uses the same frequencies as voice.  ALL voice
devices MUST be behind a filter.  ONLY the DSL device should be on the bare
wire.

nc_flyfisher wrote:
> I am preparing for DSL, and have just added a Corning DSL pots splitter
> where my service enters the house. The splitter has a Voice and a Data
> output. The incoming went to the Network terminals. The existing house
> phone wiring went to the Voice, and, from the Data terminals, I ran a
> separate phone wire to a jack by my computer. Then, to see its effects,
> I plugged in my modem (56k)to that DSL jack.
Fine, it is working like expected. The modem should not work at all!

The splitter POTS side gives a signal which is to be used by phones and 
normal modems at low frequencies.

The splitter DSL side gives only(!) the high frequencies.

In Europe we all have these splitters.
In the US often "filters" are used for the POTS lines and the DSL modem 
is directly connected to the wire. The a modem MAY also work there.

Wolfgang

Now I understand more. I finally found the specs, and see that the data
side is indeed through a high pass filter. I guess there is enough
leakage to allow the low frequency dial up signal to come through - but
low reliability slowed the apparent rate. Makes sense - and verified
that everything is working. Thanks for all the input!!


wkearney99 wrote:
> > I am preparing for DSL, and have just added a Corning DSL pots
splitter
> > where my service enters the house. The splitter has a Voice and a
Data
> > output. The incoming went to the Network terminals. The existing
house
> > phone wiring went to the Voice, and, from the Data terminals, I ran
a
> > separate phone wire to a jack by my computer. Then, to see its
effects,
> > I plugged in my modem (56k)to that DSL jack.
>
> Uh, don't do that.  A modem uses the same frequencies as voice.  ALL
voice
> devices MUST be behind a filter.  ONLY the DSL device should be on
the bare
> wire.

nc_flyfisher <ejeltrup@att.net> wrote:
> Now I understand more. I finally found the specs, and see that the data
> side is indeed through a high pass filter. I guess there is enough
> leakage to allow the low frequency dial up signal to come through - but
> low reliability slowed the apparent rate. Makes sense - and verified
> that everything is working. Thanks for all the input!!

not all splitter filters are a high pass filter for the data side. some
are just paralelled with the input...

-- 
http://www.linux-it.nl

I suspect that is true. However, I conclude that mine must be hi-pass,
since the connect rate is different than without the filter. In fact, I
expected to get the parallel type, since many schematics I saw showed
the connections that way. But, obviously, not all are.

I suspect that is true. However, I conclude that mine must be hi-pass,
since the connect rate is different than without the filter. In fact, I
expected to get the parallel type, since many schematics I saw showed
the connections that way. But, obviously, not all are. I wonder what
the advantage is fof the extra filter.