[vox-tech] OT: DSL Filters

[Marc Elliot Hall]

I have a bunch of two-line phones; and I have two phone lines.

Originally, my DSL was associated with my primary number. However, my 
provider decided to stop doing the DSL thing, which prompted me to find 
another ISP. To ensure seamless service, I activated DSL on the second 
line and then cancelled DSL on the primary number.

So, now I want to use my two-line phones with, get this, BOTH phone 
lines. Unfortunately, although they have two pairs of pins at each 
connector, it appears that my line filters (mPHASE Technologies model 
DFMU2PL1001) do not pass the second line signal through to the phones. 
Leaving the filter off allows me to use the second line, but 
periodically disrupts the DSL service and results in a low 
signal-to-noise ratio. I have tried different phone sets and different 
filters to eliminate damaged hardware as the cause of this problem.

Bad ASCII art:

Current config, one voice line working:

service entrance
  line 1	--> ===0====================+
  line 2 --> ===0===< DSL MODEM >===+|
				   |+=====\<line filter>==[phone 1]
				   +^=====/
				   ||
				   |+=====\<line filter>==[phone 2]
				   +^=====/
				   ||
				   |+=====\<line filter>==[phone 3]
				   +======/

Desired config, two voice lines working:

service entrance
  line 1	--> ===0====================+
  line 2 --> ===0===< DSL MODEM >===+|
				   ||=====\<line filter>/==\[phone 1]
				   ||=====/	        \==/
				   ||
				   ||=====\<line filter>/==\[phone 2]
				   ||=====/	        \==/
				   ||
				   ||=====\<line filter>/==\[phone 3]
				   ||=====/	        \==/

I could get a filter for the service entrance and bypass it just for the 
DSL; but that would limit my flexibility to relocate the DSL modem for 
my home network -- something I plan to do in the future, as it's an 
eyesore hanging off the wall in my library, at present.

Alternate config 1, two voice lines working:

service entrance
  line 1	--> ===0====================\<line filter>||
  line 2 --> ===0====================/		  ||
  Splitter --> ||				  ||=======\[phone 1]
	       0===< DSL MODEM >		  ||=======/
						  ||
						  ||=======\[phone 2]
						  ||=======/
						  ||
						  ||=======\[phone 3]
						  ||=======/

I could also get an adapter that splits line 1 and line 2 into separate 
cable runs, allowing individual filters for each cable and thus 
bypassing the one-signal-per filter problem. However, I already have 
enough junk hanging out of my wall jacks as it is; and doing this for 
all three of my two-line extensions would be a serious PITA.

Alternate config 2, two voice lines working:

service entrance
  line 1	--> ==0==================||
  line 2 --> ==0===< DSL MODEM >==||
				 ||=====<line filter>==\[phone 1]
				 ||=====<line filter>==/
				 ||
				 ||=====<line filter>==\[phone 2]
				 ||=====<line filter>==/
				 ||
				 ||=====<line filter>==\[phone 3]
				 ||=====<line filter>==/


Has anyone else experienced similar issues with multi-line phones? Were 
you able to resolve the problem without resorting to a filter at the 
service entrance? Can anyone recommend a line filter that will pass 
through signals on multiple pairs?

-- 
Marc Elliot Hall           www.hallmarc.net/quick_resume.html
P.O. Box 435
Shingle Springs, CA 95682
www.hallmarc.net		                      Hire me!