User Manual

Optical Master Unit
PRODUCT DESCRIPTION AND USER’S MANUAL
© Axell Wireless Ltd A1829300 rev H 14 (86)
2.1.1 Access to the System
Important Generic Information
Axell Wireless repeaters and OMUs can be configured in three different ways as regards communication
and control. They can be “stand-alone units”, “node masters” or “slaves”.
Stand-alone units do not control any other unit or take control from any other unit. All communication
with a stand-alone unit needs to be made directly with the unit – either locally or remotely via a modem or
Ethernet. Most stand-alone units are equipped with Ethernet and/or a modem for this purpose.
Node Masters keep track of the slaves that are connected to it. It is the single point of contact for alarm
reports and for heart beats in the entire system, and communicates with the AEM. All configuration and
control of all units in the network go through this Node Master. Most Node Masters are equipped with
Ethernet and/or a modem for this purpose.
Slaves are linked to a Node Master and contain a slave interface allowing for a Node Master to
communicate with the slave.
An OMU-Repeater system can be designed using repeaters that operate as slaves to the OMU or as stand alone
units regarding communication, configuration, alarms etc. Either all communication is handled by the OMU
that acts as a node master and the repeaters are slaves, or each repeater (and the OMU) handles this
communications and reporting separately.
The most common configuration is the master-slave set up which has several advantages:
 All nodes can be reached from any node in the system. An operator can log in from any node in the system
and access all parameters in all nodes, including those in the OMU
 Only one modem is needed for remote communication and configuration of the whole system
 Since the communication runs on the same fibre as the RF, this arrangement gives a reliable supervision of
the radio link. If communication between the OMU and a repeater is broken, an alarm can be generated
immediately.
Several users at a time can be logged on to the system, for instance one locally via the RS232 interface and one
remotely via modem or Etthernet. Only one user at a time can be logged in remotely.
Note! If the network has an OMU from an earlier generation
1
, there are some limitations of what can be
accessed via a local login to a slave repeater.
2.1.1.1 Local Access
Local access is achieved via an RS232 interface to the LMT port in the repeater or the OMU. This port is
accessible on the front of the OMU and inside the repeater.
2.1.1.2 Remote Access
Remote access is achieved via modem or Ethernet. Different types of modems are supported, for example
GSM, GSM-R, HSDPA/UMTS, TETRA, GPRS and PSTN.
The modem is either placed on the Control Module or as a separate unit. When cascaded OMUs are used, the
modem is placed in the OMU unit that holds the Control Module. Ethernet connection is available on the
Control Module.
1
The earlier versions of the OMU where called HUBs.