Howto:DECT Glossary

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Summary

There are some (sometimes confusing) terms which are being used in DECT systems.  Here is a brief overview.

Applies To

DECT

More Information

Terms

Term What it means
CCFP Central Controller Fixed Part
This is a unit that controls all base stations. Previously (with IP1500), the base stations were connected to the CCFP using a 2-wire cable using a proprietary interface.
With the IP1200, the bases stations are connected via IP to the CCFP. Each IP1200 includes a base station and a controller. In a multi-cell IP1200 installation, only one controller in one IP1200 is used (a.k.a. IP-Master). All other radios are controlled by this controller. The radio in this master IP1200 may or may not be used (usually it is used like a normal radio, only when the system has more than 64 base stations, the radio in the master should not be used).
DECT-Controller Shorthand for CCFP
IP-Master The IP1200 that controls all other base stations (IP1200) in the system is often referred to as IP-Master. It may or may not be identical to the Sync-Master.
Synchronization For DECT radios to communicate, they must be synchronized. In an IP1500 system, the synchronization comes from the CCFP via the 2-wire interface. In an IP1200 system though, the synchronization comes via the air. This is why an IP1200 running as radio must be located within the coverage are of another radio where it receives its sync from.
In an IP1500 system only the repeaters needed to be located within the coverage area of another radio (of course, they still need to be in an IP1200 system)
Synchronization Chain Each IP1200 radio must be synchronized to all other radios in the system. This implies that each radio (except one) needs to have another radio configured where it receives its synchronization from (through the air, see Synchronization). The one radio that does not receive sync from another radio is called a Sync-Master. All other radios receive their synchronization from this radio, either directly or indirectly.
The configuration field that is used to configure the synchronization source is rather mistitled "Sync-Master". In fact, it is not the Radio-ID of the sync master that needs to be configured here, but it is the radio ID of the radio this radio shall receive its sync from. The next radio in the sync chain if you like.
For redundancy, an "Alt-Sync-Master" can be configured. This will be used as a sync source if the radio configured as "Sync-Master" cannot be found.
It should be obvious that there must be no circles in the synchronization chain.
A repeater also needs a synchronization source, however, it cannot have an alternate source. This is a reason why you should not use a repeater as sync source for an IP1200 radio.
You can use up to 3 repeaters in a chain.
Sync-Master The radio in an IP1200 installation that is not receiving its sync from somewhere else.
Also used in the IP1200 radio configuration to configure the sync source for the radio.
Sync-Source A radio that provides synchronization to another radio.
Alt-Sync-Master An alternative sync source.
Radio A radio is either a base-station or a repeater.
Base-Station A radio that has a direct connection to the CCFP. A base station can set up a voice channel between the handset and the PBX, thus adding base stations will add channels to the system thus enlarging the number of concurrent calls possible. It also increases the systems coverage.
Repeater A radio that has no direct connection to the ®CCFP. It needs (either directly or indirectly) access to a base station that provides the channel to the PBX. A repeater increases the systems coverage thus, it does not add to the number of concurrent calls possible.
A repeater needs a sync-source (as any radio does). However, the radio serving as synchronization chain is also used to access the voice channel to the PBX. That is, calls traveling across a repeater will always also be handled by the repeaters sync source.
Repeater-Chain If a repeater itself has another repeater as its sync-source, then this is called a repeater-chain.
The radios in a repeater chain can be used as a sync-source for an IP1200 radio.
Special rules apply to create repeater chains.
Handover The process when a handset changes from one radio to another during a call.
Roaming The ability of a handset to operate in more than one DECT-system (e.g. in different locations). The handset then needs to be subscribed in all of these systems.
DECT-System A collection of radios with one controller. All of the radios in this system share a common identifier (the ARI). Handover is possible between radios within the same DECT-System.
Handset The wireless telephone.
PP Portable Part. Synonym for handset.
RFP Radio fixed part. Synonym for base station.
WRFP Wireless radio fixed part. Synonym for repeater.
ARI Access Rights Identifier. Unique identifier for a DECT-System.
IPEI International Personal Equipment Identity. Handsets have an IPEI which is effectively like a serial number to identify a handset to a DECT-system.
Q-value An indicator for the transmission quality in a given DECT call. Also referred to as Q52-value.
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