HP C7280 question

[sherwin dubren]

My HP C7280 is an all-in-one, but this question pertains to the
built in fax unit. I am having trouble attaching a common phone
line cable to it, because the longest HP cable is only 9 feet long.
The unit is designed to take a two wire (single line) cable with
the tip and ring (red and green) wires swapped around. I have no
clue as to why it is designed that way, and would like to know
the reason for it. HP makes an adapter to allow using a common
phone cable by swapping these wires, but they want over 17 bucks
for it. I have looked everywhere on the web and at local electronic
stores without success finding it. For whatever reason, this design
is a pain in the neck.

Sherwin

 

[emailaddress]

My HP C7280 is an all-in-one, but this question pertains to the
built in fax unit.  I am having trouble attaching a common phone
line cable to it, because the longest HP cable is only 9 feet long.
The unit is designed to take a two wire (single line) cable with
the tip and ring (red and green) wires swapped around.  I have no
clue as to why it is designed that way, and would like to know
the reason for it.  HP makes an adapter to allow using a common
phone cable by swapping these wires, but they want over 17 bucks
for it.  I have looked everywhere on the web and at local electronic
stores without success finding it.  For whatever reason, this design
is a pain in the neck.

                           Sherwin

Are you 100% certain it is wired as you describe? Normally a standard
telephone cable is used, have you tried using one?

If all you need, and you really do need to swap the red and green TX/
RX wire pair, get a snap apart coupler like the following, upon
opening it you should be able to either swap the pins using common
hand tools, or at worst solder the wires reversed.

http://www.google.com/products?q=phone coupler

These are just examples, you can probably pick one of these up at
several stores locally for $2.

 

[sherwin dubren]

Are you 100% certain it is wired as you describe? Normally a standard
telephone cable is used, have you tried using one?

Yes, I tried a two wire and a four wire cable and neither worked. The
HP fax test indicated problems with both. I don't know why HP decided
to wire their fax outlets this way. They should have reversed the
leads internally, so adapters would not be required. It does kind of
force people to buy their 'special' phone cables.

If all you need, and you really do need to swap the red and green TX/
RX wire pair, get a snap apart coupler like the following, upon
opening it you should be able to either swap the pins using common
hand tools, or at worst solder the wires reversed.

http://www.google.com/products?q=phone coupler

These are just examples, you can probably pick one of these up at
several stores locally for $2.

Have not found a local store yet that sells these couplers.

Sherwin

 

[emailaddress]

   Yes, I tried a two wire and a four wire cable and neither worked.  The
   HP fax test indicated problems with both.  I don't know why HP decided
   to wire their fax outlets this way.  They should have reversed the
   leads internally, so adapters would not be required.  It does kind of
   force people to buy their 'special' phone cables.




   Have not found a local store yet that sells these couplers.

                             Sherwin

Try places like Walmart, Radio Shack, Best Buy, Fry's, Circuit City
(if any are still open in your location), or of course a telephone
store (corded, AT&T generally not just a cellphone store).