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Page 28
Black Box Short Range Modem
B. CABLE RECOMMENDATIONS
All Black Box Short Range Modems are tested to the distances published in our Cata-
logs and Specification Sheets on twisted-pair cable with the following characteristics:
We fully expect that the Short Range Modems will operate on lines with specifications
different from those tested, but to reduce the potential difficulties in the field, one
should ensure that the cable being used has similar or better characteristics (lower
capacitance or lower resistance).
Wire with capacitance of 20pF/ft. or less is suitable for all our Short Range Modems
however, distances may vary from those published in our catalog. Resistance will also
affect distance but not functionality. Wire should be 26 ohms (.4mm) or larger (smaller
AWG#).
Black Box products are designed to withstand normal environmental noise and condi-
tions however, other environmental factors too numerous to discuss in this format may
affect proper operation of the SRM’s.
Selection of the proper SRM for an application is critical to maintaining Customer Sat-
isfaction and should be taken seriously. Certain SRM configurations are better suited
for particular applications and environments than others.
Wire Gauge
Capacitance
Resistance
19 AWG(.9mm)
83nF/mi or 15.72 pF/ft.
.0163 ohms/ft.
22 AWG(.6mm)
83nF/mi or 15.72 pF/ft.
.0326+/ft.
24 AWG(.5mm)
83nF/mi or 15.72 pF/ft.
.05165 ohms/ft.
26 AWG(.4mm)
83nF/mi or 15.72 pF/ft.
.08235 ohms/ft.
Summary of Contents for ME475A-R2
Page 1: ...ME475A R2 Async Sync Short Haul Modem...
Page 32: ...ME475A R2 version 1...
