Re: [hylafax-users] Question about a modem

["Jay R. Ashworth" <jra@baylink.com>]

On Wed, Oct 24, 2001 at 06:15:27PM +0200, Giulio Orsero wrote:
> On Wed, 24 Oct 2001 11:47:47 -0400, you wrote:
> >> However, I've another modem that does not work because it wants only 2
> >> wires phone cables, while the VoIP cable is 4 wires; this modem always
> >> "hears" RINGs on the line while there's none.
> >
> >Henh?  I'm not aware of *anything* that's four-wire, except MultiTech
> >leased line analog modems...
> 
> When you look at the plastic end of the phone/modem cable, there are
> some phone/modem cables that have 4 golden metal stuff attached to
> yellow, green, red, blu/black wires, other just 2 (green/red).

Ah.

> The first kind of modem I have will work with both kind of cables, the
> 2nd type only with 2 wires cables.
>
> Note, that I don't know anything about the structure or
> functioning/purpose of those wires, just that some have 2 some 4 :-)

The problem is that some devices actually *pay attention* to the second
pair on an RJ-14, and what those wires do is not always defined the
same way.

In any event, using a 2 wire cable on such devices should ameliorate
problems without losing any functionality: all PSTN dialup devices
should -- by definition -- work fine on one pair.  If your VoIP box
*requires* a 4 wire cable to do *anything*, there's probably something
misconfigured about it.

Note that the fact that it's *shipped* with a 4 wire cable has no
bearing whatever on whether it will *work* with only 2 wires; 2-pair
cables are the most common.

Cheers,
-- jra
-- 
Jay R. Ashworth                                                jra@baylink.com
Member of the Technical Staff     Baylink                             RFC 2100
The Suncoast Freenet         The Things I Think
Tampa Bay, Florida        http://baylink.pitas.com             +1 727 804 5015

   "Usenet: it's enough to make you loose your mind."
     -- me


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