User guide

TD 92422GB

18 February 2010 / Ver. E

System Planning

Ascom IP-DECT System

In addition to the above automatic synchronization procedure there is also possible to use

static synchronization by manually lock on to a specific RFPI. However when specifying a

specific RFPI the RFPI must be for a RFP within the same synchronization region.

7.4 Sync Master IPBS

Radios configured as sync master will report to the Pari Master that it wants to be a sync

master. The Pari Master will select one of them to be the active sync master.

When a sync master has been assigned to be active it searches for other IPBSs within the

same region during 30 seconds. If any IPBS is found the values for slot, frame, multi frame

and PSCN are received and applied to the Sync Master. After receiving all these values or

after the time-out of 30 seconds the Sync Master enters the master state.

With this method it will be possible to restart only the Master in the region. The remaining

slaves will be able to maintain synchronization for a few minutes during restart of the

Master. The Master will adjust itself to the other IPBSs at startup. The slaves will notice that

the Master is back and the synchronization will be received from the Master.

In master state the values are updated locally during all further operation of the Master

IPBS and no synchronization to other IPBSs in the same region is done.

It is possible to configure the Sync Master to synchronize to a reference base station

(another or same DECT system). In this case the Sync Master will try to synchronize to the

reference system if the reference system is found but it will not require the reference

system to be available. The Sync Master will operate even though the reference system is

not available. During startup the Master will prefer to synchronize to a slave base in the

same system before synchronizing to the reference base station.

7.5 Standby Sync Master IPBS

Radios configured as sync master will report to the Pari Master that it wants to be sync

master. The Pari Master will select one of them to be sync master and the others will be set

to standby sync master.

Only one Sync Master needs to be configured for a synchronization region. But if this

single IPBS fails, the entire synchronization region will fail. It is therefore possible to set

several radios as sync masters to achieve standby sync master functionality. In case

reference sync is used on the sync master remember to also configure reference sync on

the standby sync masters. The actual RFPIs used as reference sync may differ on the

different sync masters as they are positioned at different locations.

If the sync master goes down, the Pari Master will assign one of the standby sync master

to be active sync master.

7.6 Ring Synchronization IPBL

The IPBL is synchronized by a cable. The synchronization support up to 100 IPBLs in one

ring. Each synchronisation ring dynamically assigns a sync Master. The length between two

IPBLs must not exceed 2000 metres.

The signalling is made with RS422. Each port has two transmit (TX) and two receive (RX)

signals. This means that each port uses 4 pairs of cable.

If the synchronization ring runs outdoors, for example between two buildings, a fibre optic

cable can be used. The total length of a mixed cable (fibre optic and copper) is unchanged

at 2000 metres.