User guide

A-16 Encore Multi-port DSU/CSU User GuideÑJuly, 1997

¥ Calculate the T1 transmission using this formula:

L1 + L2 + L3 = 15 to 22.5 dB

The sum of the two losses, L1 and L2, plus any LBO (Line Build Out) must be

greater than 15 dB and less than, or equal to, 22.5 dB at 772 kHz.

¥ Select the required LBO so that: L1 (phone company) + L2 (your loss due to cable

length) + L3 (your LBO switch setting) = greater than 15 dB but less than 22.5 dB.

Example

L1 = 11 dB (Obtained from phone company)

L2 = 2 dB (Premises cable length is 400 ft., 1dB per 200 ft.)

LBO = 7.5 dB selected because:

11 dB(L1) + 2 dB(L2) + 7.5 dB(L3) = 20.5 dB which is between 15 dB and

22.5 dB, as required.