Media5 Mediatrix 4116, Руководство по установке оборудования

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Loop Current vs Cable Length Hardware Installation Guide
Mediatrix 4100 – Analog Access Device 35
Loop Current vs Cable Length
When installing the Mediatrix 4100, be sure that the cable length is not too long for the loop current.
Considering the following operating parameters:

Standard analog devices such as telephones or faxes with typically 300 Ohms of DC
impedance.

Cable with 85 Ohms/Km (AWG26)

0 dBm signal at interface
Observe the following values:
Rdc max includes both equipment (standard analog telephones or faxes) and cable DC resistance. This is
illustrated in
Figure 13 on page 35 .
Figure 13: Max DC Resistance
Table 17: Max DC Resistance
Loop Current
in mA
Maximum Cable
Length in Meters
Rdc Max in
Ohms
20 2100 660
25 1000 470
30 450 375
32 300 350