[net.dcom] Questions about Noisy Lines

mule@inmet.UUCP (02/02/85)

I am using a 1200 baud modem over a voice grade line and
am getting a LOT of static.  At first the line was completely
unusable, but a guy came out and adjusted the "level" (he said it
was "hot" at my end - the origninate end) and now I'm down to
an error about every 10-15 seconds.  

I've tried to get AT&T to look at it, but they say the line is
up to "voice-grade" specs and refuse to do anything more (I was
going to order a "data-grade" line but was told it would take 6
months to install).

Is there anything I can do myself.  What does adjusting the "level"
mean and can I do it myself ?  I have the feeling that another 
adjustment might be all it would take to fix the problem. One anomaly 
is that while I get almost continual errors in transmission from 
the mainframe to my terminal, there are absolutely no errors 
in the other direction (I dial up to the mainframe so the
frequency is higher coming back, but it's hard to believe that
the difference is just the difference in frequency - or is it ?)

If there are answers to these questions in a book, please point
me towards it.

Thanks,

	Fred Mueller

tracyw@islenet.UUCP (Tracy Walters) (02/07/85)

In Article <1938@inmet.UUCP>, Fred Mueller writes:
>I am using a 1200 baud modem over a voice grade line and
>am getting a LOT of static.  At first the line was completely
>unusable, but a guy came out and adjusted the "level" (he said it
>was "hot" at my end - the origninate end) and now I'm down to
>an error about every 10-15 seconds.

You didn't mention what type (Brand name and model) of modem you have.

>I've tried to get AT&T to look at it, but they say the line is
>up to "voice-grade" specs and refuse to do anything more (I was
>going to order a "data-grade" line but was told it would take 6
>months to install).

They are also very expensive!

>Is there anything I can do myself.  What does adjusting the "level"
>mean and can I do it myself ?  I have the feeling that another
>adjustment might be all it would take to fix the problem. One anomaly
>is that while I get almost continual errors in transmission from
>the mainframe to my terminal, there are absolutely no errors
>in the other direction (I dial up to the mainframe so the
>frequency is higher coming back, but it's hard to believe that
>the difference is just the difference in frequency - or is it ?)

Adjusting the level is tweaking the power output from your keyer (I assume from
this that you are at your office and not at home) and usually requires some 
specialized test equipment and knowledge. My advice would be get somebody that
knows how. The possibility exists that your modem's receiver is having trouble
with the lower frequency.
Would it be possible for you to take your modem (terminal and all if easier) to
another phone line and check it out? Might save you some expense and hassle if
that turns out to be the case. A correctly aligned voice grade line SHOULD
not have any difficulty with a modem's carrier frequencies, after all, they
were designed with that specific purpose in mind. 

tracyw at Islenet, Honolulu Hi

Beaches, Bikinis & Beer

While the rest of the nation,
And all the population,
are enjoying the snow and cold,
We in Hawaii must endure the same old
Sunshine, Skin and Scotch whiskey.

(I know the last line doesn't rhyme, but I was busy staring at Amy Lou Buckner
in poetry class)
:->