User`s guide

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This value should be set to the maximum over-the-air data packet
duration. For instance, for a maximum CAI packet size of 512 bytes,
the value should be set to 750 ms. The value for Data FSSP may range
from 0 to 5000 ms in 50-ms increments.
Note: For proper operation on a channel with ASTRO voice present,
this field should be set to no shorter than 200 ms due to the ASTRO
voice frame size. For more details on data channel access
operation, refer to the APCO 25 Common Air Interface
Operational Description for Conventional Channel.
Data Tx Short Random Range
(ms)
This field will be visible for Mobiles only. Use the UP/DOWN arrow keys
to select the Data Tx Short Random Range value or enter a value
directly. Before the radio can transmit a data packet, it must check the
channel status to verify that the channel is clear. The data channel
access process checks this status on a random basis. This timer
represents the MAXIMUM time that the radio will wait after it has
received the FIRST qualified Frame Sync Sequence to check status.
Increasing this value reduces the potential of collision with other
radios attempting to transmit data (seize the channel), but it also
increases the channel access delay. This value may range from 50 to
500 ms in 50-ms increments.
Note: For more details on data channel access operation, refer to
the APCO 25 Common Air Interface Operational Description for
Conventional Channels.
Data Tx Long Random Range
(ms)
Use the UP/DOWN arrow keys to select the Data Tx Long Random
Range value. This value may also be entered directly. This field
indicates the upper bound of the uniform random range for the back
off delay period after the radio senses a busy channel status symbol for
normal Tx messages. Before the radio can transmit a data packet, it
must check the channel status to verify that the channel is clear. The
data channel access process checks this status on a random basis.
If the Common Air Interface (CAI) data packet to be transmitted is
other than an acknowledgment, this timer represents the MAXIMUM
time that the radio will wait after it detects a BUSY Channel Status
Symbol to re-check the Channel Status Symbols for permission to
transmit. This value may range from 50 to 5000 ms in 50-ms
increments.
Note: For more details on data channel access operation, refer to
the APCO 25 Common Air Interface Operational Description for
Conventional Channels.
Data Tx Resp Random Range
(ms)
Use the UP/DOWN arrow keys to select the Data Tx Response Random
Range value. This value may also be entered directly. Before the radio
can transmit a data packet, it must check the channel status to verify
that the channel is clear. The data channel access process checks this
status on a random basis.