Company Confidential
28
Raveon Technologies Corp.
1300-
1399. When properly configured, the two groups will not receive each other’s
signals.
A way to disable addressing altogether is set the Address Mask to 0000 (
ATMK
0000 command). This tells the RV-M29 to ignore the address, and receive every
transmission.
For a unit to receive a message from another unit, all of the following conditions
must exist:
•
The bits in the TOID of the sending unit must match the bits in the MYID of the receiving unit
that are designated in the address mask.
•
If encryption is used, the KEYPHRASE of both units must match.
Broadcast Transmissions
The double FF is used to identify a broadcast packet. A transmission with a two
digit FF in the first two positions of the destination ID, or in the last two positions of
the destination ID, will be interpreted as a broadcast, and any modem with an ID
that matches the two non-FF digits will receive the data. For example, sending
data with a destination ID of 12FF will be received by any modem with a unit ID
1200 through 12FF. Sending data with a destination ID of FF34 will be received by
any modem with a unit ID of 0034 through FF34.
The Address Mask
Only in systems where some modems should only talk to certain other modems,
might you want to change the address mask. Whenever data is received over the
air, the Destination Address of the transmission is logically “ANDed” with the
Address Mask in the receiving modem. This is the
Effective Destination Address
.
The receiving
RV-M29
also ANDs its own Unit Address with its Address Mask. The
result is the
Effective Unit Address
.
Addressing Examples:
Example 1 (default configuration)
Sending
RV-M29
Unit Address = 0001
Sending
RV-M29
Destination Address = 0001
Receiving
RV-M29
Unit Address = 0001
Receiving Unit’s Address Mask = F000
Result: Unit will receive the data, because the addresses identically match. When the
addresses are identical, the value of the mask is not important.
Notes: This is the default configuration. All units have address 0001, and all modems will talk to
all other modems with address 0001.
Example 2 (a configuration that won’t work)
Sending to Destination Address =
1001
Receiving Unit Address =
0001
Receiving Unit’s Address Mask =
F000
Result: No data will be received, because the address do not match, and the address mask of
FFFF requires that at least the first digit match. .
