11021-511-B4-002, Rev. B
2.0 Theory of Operation
The FlexNet MPS48-7M multipurpose power supply provides fi ltered 50W output power for a typical
48V telecom bus during normal line operation. During line disruptions, the MPS48-7M supplies
uninterrupted output power of 50W directly from a string of four 12V batteries.
Metal oxide varistor (MOV) technology provides line voltage surge suppression in the event of line
cross or power spikes. An electromagnetic fi lter conditions line voltage, enabling the power supply
to operate in compliance with FCC Class A standards. The AC-to-DC converter feeds power to the
primary winding of a high-frequency isolation transformer. The resulting DC output, at the secondary
of the transformer, provides power to the load and charges the 48V string batteries, keeping them
fully charged in preparation for a line disruption. MPS48-7M battery temperature compensation range
is from -0ºC to 40ºC. A battery heater mat option extends battery life in cold environments. Maximum
output voltage of 56Vdc.
The power module provides over-current, over-voltage, and short-circuit protection. After the fault
is cleared, the power module automatically resumes power to the load. The control logic circuitry
provides a LVD (low battery voltage disconnect), detects the presence (or absence) of batteries,
performs periodic battery testing, and communicates status locally with LED status indicators.
Preconnectorized cables of varying lengths provide reliable and effi cient fi eld installation. Ethernet,
48Vdc power (with return), and RS232 interface are supported on the preconnectorized cables.
The MPS housing is constructed of weather resistant powder coated aluminum. The enclosure can be
pole or wall-mounted.
AC service is routed into the bottom of the enclosure through a 1/2" Electrical Metallic Tubing (EMT)
knockout located in the bottom center of the enclosure. The data and power cables are routed
through a provided 3-hole strain relief fi tting. Additional 1/2" and 3/4" knockouts are provided at the
back, bottom, and sides of the enclosure.
The MPS48-7M interface module includes:
• An RJ11/RJ45 pair of connections support a mesh router. The RJ11 includes the RS232
connection to the router. The RJ45 provides an Ethernet connection between the router and
48VDC power (and return).
• An RJ45 for connection to a remote router or modem (Ethernet backhaul).
• An RJ11 Craft Port connection providing an RS232 connection to the mesh router for network
management information.
• A 48Vdc terminal block for an auxiliary piece of equipment (e.g. a camera).
Aux Radio,
Power Ethernet
Backhaul Radio, Serial Local Craft
Terminal Block RJ45 RJ45 RJ11 RJ11
Pin Pin Pin Pin Pin
1 +48Vdc 1 Data
Pair 1 1 Data Pair 1 1 NC 1 NC
2 Return 2 Data
Pair 1 2 Data Pair 1 2 Radio TX 2 Local RX
3 Data
Pair 2 3 Data Pair 2 3 Return 3 Return
4 +Vdc 4 NC 4 Radio RX 4 Local TX
5 +Vdc 5 NC 5 NC 5 NC
6 Data
Pair 2 6 Data Pair 2 6 NC 6 NC
7 - Vdc 7 NC
8 - Vdc 8 NC
Table 2-1, Network Connections