Application Notes

Operation of a Temporary Address

OPERATION OF A TEMPORARY ADDRESS

Group Messaging

The FLEX protocol allows for a dynamic group call for the purpose of sending a common message to a group of paging devices. The dynamic group call approach assigns a “Temporary Address”, using the personal address and the short instruction vector. The temporary address must be disabled by the host after the message is completed.

The FLEX protocol specifies sixteen addresses for the dynamic group call, which may be temporarily activated in a specific future frame (If the designated frame is equal to the present frame, the host is to interpret this as the next occurrence of this frame 4 minutes in the future.) The temporary address is valid for one message starting in the specified frame and remaining valid throughout the following frames to the completion of the message. If the message is not found in the specified frame (frame defined by a full 7-bit frame number), the host must disable the assigned temporary address.

The following describes the sequence of events between the Host and the FLEXchip IC required to handle a temporary address:

1.Following an Address Packet, the host will receive a Vector Packet with

V2V1V0 = 001 and i2i1i0 = 000 for a Short Instruction Vector indicating a temporary address has been assigned to this pager. The vector packet will indicate which temporary address is assigned and the frame in which the temporary address is expected.

2.The FLEXchip IC will increment the corresponding temporary address counter and begin to decode all of the following frames.

3.The FLEXchip IC continues to decode all of the frames and passes any address information, vector information, and message information to the host, followed by a status packet indicating the end of each frame and the current frame number.

4.There are several scenarios that may occur with temporary addresses.

a.The temporary address is not found in the frame assigned and therefore the host must terminate the Temporary Address mode by sending an All Frame Mode Packet to the FLEXchip IC with the “DTA” bit of the particular temporary address set.

b.The temporary address is found in the frame it was assigned and was not a fragmented message. Again, the host must terminate the Temporary Address mode by sending an All Frame Mode Packet to

Application Notes

Operation of a Temporary Address

the FLEXchip IC with the “DTA” bit of the particular temporary address set.

c.The temporary address is found in the assigned frame and it is a fragmented message. In this case, the host must follow the rules for Operation of a Fragmented Message and determine the proper time to stop the All Frame mode operation. In this case, the host must write to the “DAF” bit with a “1” and the appropriate “DTA” bit with a “1” in the All Frame Mode Register in order to terminate both the fragmented message and the temporary address.

5.The above operation is repeated for every temporary address.

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