DATA-LINC GROUP
28
PN 161-09981-002C
rev 8/04
DDAA1000/SRM User Guide
Main Menu Option (3): Edit Radio Transmission Characteristics
When option (3) is selected in the main menu the screen in figure 14 appears, which allows the user to modify the radio
transmission characteristics of the radio modems. As stated in the warning, these parameters are for the experienced user
who has a good understanding of the principles of radio data transmission. They should be changed only after consulting this
user guide.
It is important to note that the radio parameters between any radio modems in communication will be determined by the
settings for the master (except when in multi-point mode, see (4) RF Data Rate below). While the settings may be modified
for the remote(s) and/or repeaters, they will be overridden by the master’s parameters.
Figure 14: Radio Parameters Menu
Shown below are example settings. Please refer to supplied configuration sheets for your modem’s configuration.
(0) FreqKey
Selection (0) in the Radio Parameters menu allows the user to modify the hopping patterns of the radio modems to
minimize the interference with other Data-Linc Group radios in operation in the area. For instance, if there were 10 pairs
of Data-Linc Group radios in operation within a factory or refinery, changing the Frequency Key would ensure that they
would not jump onto the same frequencies at the same time for the same length of time.
There are 15 choices available for the Frequency Key (0-9 and A-E). It is recommended that a list be maintained of the
settings for each master to ensure that each is set to a different hopping pattern.
(1) Max Packet Size and (2) Min Packet Size Selections
For DDAA1000/DD1000 use the user should not change this parameter.
(1) and (2) allow the user to designate the size of the packets (in bytes) used by the radio modem in its communication
link. Packet size is determined by a combination of the settings entered by the user and the RF Data Rate. In addition,
the Max Packet Size is a function of the setting selected for the Min Packet Size. Tables 3, 4 and 5 provide the packet
sizes for each different combination of settings.
