[asterisk-users] ISDN config: LBO values

[Tilghman Lesher]

On Saturday 15 May 2010 19:28:37 Jaap Winius wrote:
> When configuring Asterisk with an ISDN card, it will at one point
> become necessary to select the LBO (Line Build-Out) value. This is an
> integer (0-7) that is determined by the length of the cable and is
> selected from the following table. Many of us are familiar with it:
>
>          CSU (dB)   DSX-1 (feet)
>     -------------------------------
>     0    0          0?133
>     1               133?266
>     2               266?399
>     3               399?533
>     4               533?655
>     5    -7.5
>     6    -15
>     7    -22.5
>
> The value selected should almost always be zero. However, if the cable
> is of a significant length, another value must be selected, but which
> one? There are two columns: CSU and DSX-1. When is it appropriate to
> use the one or the other to determine the correct LBO value?

Each LBO value is a different amount of loss to be expected on the line, and
therefore the signal is amplified a commensurate amount.  What it really comes
down to is what works for you.

-- 
Tilghman Lesher
Digium, Inc. | Senior Software Developer
twitter: Corydon76 | IRC: Corydon76-dig (Freenode)
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