DSL and caller ID, TDD, and alarm systems

Are there an special provisions needed for DSL and caller ID to exist peacefully together?

My parents are getting DSL, and plan on getting caller ID in the future. I am under the impression that they must have an external DSL splitter (or filter) for caller ID to function correctly. Is this true?

Same rules for alarm systems and TDD? Please set me straight. Thanks, Tim C.

Reply to
Tim C.
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No. They happily coexist as long as all analogue devices use microfilters.

Reply to
David H. Lipman

There isn't any problem with caller ID and dsl, provided that all telephony devices are filtered.

Apparently, alarms can cause problems, unless carefully filtered. Best is to go with a whole house POTS splitter if you plan to use an alarm system.

Reply to
Neil W Rickert

David and Neil,

I thought the caller ID couldn't get past the phone filters to the phones ??? .....apparently it can.

thanks for the responses, Tim

Reply to
Tim C.

Thanks Arnie. Good job on the diagram - - I can see that caller ID works even thru the filter.


Reply to
Tim C.

Here is how I do it. The DSL kit came with 4 filters but I only use one to filter everything including the Caller ID device

_________ Telco _DSL __________________________________! ! Connector / Modem ! PC ! Block ___/_________ !_________! ==== ! Radio Shack! ! [ ] Line __! Duplex Jack! ! ==== ! 279-448 ! ! !____________! ! \ ________ ! \_ DSL___! Radio !_$$_ WECO Key equip ! Filter ! Shack ! with 3 telephones ! ! !_$$_ Fax Dial Up from PC _______! ! Wiring !

! Block !__ Panasonic KG XT 5110 2 phone ! !

! 279-430!___Acatel 2840 Webtouch Phone ! with dial up access ! !__ AT&T 612 desktop phone ! ! ! !__ Radio Shack Wall Phone

! ! ! !_$$_ 2 Dish Network Receivers ! ! !________!___AMCAMEX Caller ID Display

$$ indicates the use of either Radio Shack Single or Duplex Jack to facilitate quick disconnect for testing purposes.

Reply to
Arnie Goetchius

Hi Tim,

None. A phone line passes all frequencies the cable is capable of handling and standard telephones use just a small part of the frequency spectrum available (~300Hz - 3400Hz), which are just VOICE FREQUENCIES. Caller-id uses this bandwidth to receive its info from the exchange, which is (usually) sent as a 300bps modem data string between ring signal 1 and ring signal 2.

DSL uses frequencies way above human hearing so it does not clash with Caller-id or in fact ANY Voice Frequency operation. These are HF and VHF frequencies

The "DSL Filter" that is needed is simply to remove the DSL HF & VHF from the line, before the voice LF signals are passed to the telephone hardware, as some older telephone H/W does not like the DSL frequency signal present in what they see.

No, it can be an internal or external splitter, it won't matter to caller-id as it operates strictly within the LF signals that standard telephones use. Consider a Caller-id device as if it was just a standard telephone, so it should be AFTER a splitter/filter, just like a standard telephone. My preference is to use a single external splitter for all the phones in the house and take the ADSL signal off the line before it reaches the DSL splitter.

This is where it gets tough, it all depends on exactly HOW the alarm system works (I am not sure what a TDD is but will assume its like an alarm that needs a "clear line" to operate). Some alarms MUST have a clear line to work, so they intercept the cable coming into the house and BREAK the line at that point when the alarm is triggered, so they can guarantee they have a working telephone line that can reach the exchange. In this case DSL should still work, unless there is something specific in your Alarm system that says it cannot. I suggest you contact your Alarm manufacturer to clear this point up, BUT don't be surprised if the Alarm people say "whats DSL"?


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