FIELD NOTICE

Connecting InfiNet Wireless units to a DC power supply

Tech support cases analysis indicates that a certain number of unit failures happen upon incorrect DC power supply connections. This paper is aimed to provide essential guidelines on DC power supply usage.

Using DC power supply: the correct way.

Most CPE units (such as R-5000-L, R5000-Lm, R5000-S/Sm/Smb,R-5000-Smc) require power supply voltage of +9...+56VDC.

Top-line products including base stations and InfiLINK 2x2 PRO units (R5000-Mmx/Mmxb, R5000-Omx) support a broader power supply voltage range of ±43VDC ... ±56VDC.

Several IDU units are available for different conditions, including IDU-LA-G (IDU-LA) for DC-powered installations. This power injector supports input voltage of +12..+48 VDC and should be properly grounded.

The correct connection scheme ensures safe and trouble-free link operation.

Connecting -48VDC power supply

As common telecom equipment utilizes -48VDC power supply, this voltage is readily available on most installation sites. This power supplies can be used with IW base stations and InfiLINK 2x2 PRO units without limitations.

However, some users believe that connecting neutral terminal of the -48VDC power supply to the line terminal of the IDU, and line terminal of the power supply to the neutral terminal of the IDU would reverse the -48V voltage to +48V, which is suitable for all other IW models. While this hypothesis is true in terms of electrical potential difference, such connection scheme also creates a short circuit due to the fact that neutral lines in DC-powered equipment are grounded. Once the system is powered on, this short circuit causes rapid current growth, permanently damaging IDU, ODU and possibly the power supply itself. Note that using incorrect power supply voltage voids unit warranty!

NEVER ATTEMPT TO REVERSE CONNECT A -48VDC POWER SUPPLY TO INFINET WIRELESS EQUIPMENT!

Using DC/DC voltage converter

The only possible solution for using a -48VDC power supply with IW units is to install a DC/DC voltage converter, such as MSTronic MIT-35G or similar between the power supply and the IDU.

Ensure that the converter output matches the required power voltage parameters before powering on the unit.