[Asterisk-Users] ADSI phone vs. IP phone

[Ken Alker]

--On Monday, January 19, 2004 11:01 AM -0500 Andrew Kohlsmith 
<akohlsmith-asterisk at benshaw.com> wrote:

<SNIP>

> IP phones are nice, I'll give them that... but they are also a pain in
> the  ass if you're upgrading/retrofiting an office, and they also don't
> play  well together -- you're more or less stuck using one brand of POE
> switch  with one brand of IP phone, or you use wall-warts.  ADSI phones
> "feel" much  more phone-like to me, even though IP Phones can do some
> wild things.

Andrew,

If I read above correctly, you imply that ADSI phones don't need wall-warts 
(A/C power transformers that plug into the wall).  I'd assume that based on 
the sizable LCD screen, potential back-lighting, microcontroller(s), etc, 
that an ADSI phone would have to have a wall-wart, especially if you wanted 
to use any of its functionality while it is on-hook.  I have designed a 
phone or two in my past (many years ago) and, as I recall, there is almost 
*no* current available from the telco while a phone is on-hook.  You might 
be able to trickle-charge a very small battery, or run an RCA 1802 
processor (microamps), but that's about it.

Did I read your statement correctly, or do ADSI phones truly require 
wall-warts (as do SIP phones)?