I will say from the start, I
am not really a fan of these tests unless
there is a valid reason you feel they are
necessary. Most analoge modems today
are in chip form, pre-designed and are so
integrated there is little or almost nothing
you can do to improve the performance from
the IC.
At best, you must follow good layout
guidelines and pay VERY CLOSE ATTENTION TO
GOOD GROUNDING AND A QUIET VCC.
Today, most modems are made
from highly integrated modem chipsets.
They are like a microprocessor, 99% of of
the design is inaccessible. Also,
there are many... MANY different ways to
apply performance tests... who's modem are
you testing against (as your reference)?,
what characteristics of the line will you
use?, (there are many), what speeds will you
test?, are you originating or answering
(again, to who's modem)?, should you use
"like" modems at both ends?, (there are many
reasons to say NO!... analogue/digital
"like" modems are designed for optimum
performance to themselves), what defines
marginal connection?, (in what combination
of all the variables?)... the questions go
on and on. Results are up to
interpretation and vary tremendously.
Before you start any testing
program, you might ask the big question...
what will you do if the performances is
'under par'??? (Don't forget to define
'par').
Disclaimer... This
information is only for your reference,
it is not 'gospel'. Actual tests
available vary greatly depending on
performance concerns. I suggest you
generate a clear definition of your
intent before you begin this process.
Anyway, here is a terse list
of some performance certifications for PSTN
(dial-up) modems. At the very bottom
of this page, are two links for more
information... I am not associated with
those links and I only give you them for
your reference.
1. ANSI/TIA TSB-37A
and TSB38
TSB37A specifies
the telephone network model intended to
be representative of the transmission
impairment conditions encountered in
North America (US and Canada).
TSB38 specifies
the standardized procedures for testing
2-Wire 4-Kilohertz Voiceband Duplex
Modems that operate over PSTN.
2.
ITU-T Recommendation
V.56bis and V.56ter
V.56ter specifies
the standardized procedures for testing
2-Wire 4-Kilohertz Voiceband Duplex
Modems that operate over PSTN.
V.56bis specifies the telephone
network model intended to be
representative of the transmission
impairment conditions found on networks
within North America, Europe and Asia.
Additionally, it has been adjusted to
account for the presence of the large
PBX (Private Branch Exchange) system
commonly found in business environments.
3. ANSI/TIA SP-3857
and TSB38 (for testing to V.90 speeds)
SP-3857 North
American Telephone Network Transmission
Model for Evaluating Analog Client and
Digitally Connected Server Modems” (if
approved in 2007), will be reaffirmed as
TIA/EIA-793)
TSB38 specifies
the standardized procedures for testing
2-Wire 4-Kilohertz Voiceband Duplex
Modems that operate over PSTN.
4. TBD
In Process... visit later
5. TBD
In Process... visit later
6. TBD
In Process... visit later
7. TBD
In Process... visit later
