AeroComm Corporation 44249AJ Manuale Utente
5
5
5
5////8/2007
8/2007
8/2007
8/2007
29
29
29
29
Leaving RTS disabled for too long can cause data loss once the transceiver’s receive buffer
Leaving RTS disabled for too long can cause data loss once the transceiver’s receive buffer
Leaving RTS disabled for too long can cause data loss once the transceiver’s receive buffer
Leaving RTS disabled for too long can cause data loss once the transceiver’s receive buffer
fills up.
fills up.
fills up.
fills up.
fills up.
5.1.5
5.1.5
5.1.5
5.1.5 9600 Baud/Packet Frame (pin 12)
9600 Baud/Packet Frame (pin 12)
9600 Baud/Packet Frame (pin 12)
9600 Baud/Packet Frame (pin 12)
9600_BAUD
9600_BAUD
9600_BAUD
9600_BAUD – When pulled logic Low before applying power or resetting, the transceiver’s
serial interface is forced to a 9600, 8-N-1 (8 data bits, No parity, 1 stop bit) rate. To exit,
transceiver must be reset or power-cycled with 9600_Baud logic High.
9600_BAUD should only be used to recover the radio from an unknown baud rate and
should not be used during normal operation. When 9600_BAUD is pulled logic Low,
Broadcast Mode is disabled.
serial interface is forced to a 9600, 8-N-1 (8 data bits, No parity, 1 stop bit) rate. To exit,
transceiver must be reset or power-cycled with 9600_Baud logic High.
9600_BAUD should only be used to recover the radio from an unknown baud rate and
should not be used during normal operation. When 9600_BAUD is pulled logic Low,
Broadcast Mode is disabled.
Packet Frame
Packet Frame
Packet Frame
Packet Frame – When enabled in EEPROM, Packet Frame will transition logic Low at the start
of a received RF packet and transition logic High at the completion of the packet.
of a received RF packet and transition logic High at the completion of the packet.
5.1.6
5.1.6
5.1.6
5.1.6 RSSI (pin 13)
RSSI (pin 13)
RSSI (pin 13)
RSSI (pin 13)
Received Signal Strength Indicator is used by the Host as an indication of instantaneous signal
strength at the receiver. The Host must calibrate RSSI without a RF signal being presented to
the receiver. Calibration is accomplished by following the steps listed below to find a
minimum and maximum voltage value.
strength at the receiver. The Host must calibrate RSSI without a RF signal being presented to
the receiver. Calibration is accomplished by following the steps listed below to find a
minimum and maximum voltage value.
1) Power up only one Client (no Server) transceiver in the coverage area.
2) Measure the RSSI signal to obtain the minimum value with no other signal
present.
3) Power up a Server. Make sure the two transceivers are in close proximity and
measure the Client’s peak RSSI once the Client reports In Range to obtain a
maximum value at full signal strength.
maximum value at full signal strength.
Figure 1 shows approximate RSSI performance. There are two versions of receivers used by
the AC4424. As of January of 2003 forward, only the new revision receiver will be shipped.
The RSSI pin of the former revision requires the Host to provide a 27k pull-down to ground.
the AC4424. As of January of 2003 forward, only the new revision receiver will be shipped.
The RSSI pin of the former revision requires the Host to provide a 27k pull-down to ground.
A table of board revision history is provided below. No R
No R
No R
No RSSI pull
SSI pull
SSI pull
SSI pull----down should be used with
down should be used with
down should be used with
down should be used with
the new revision.
the new revision.
the new revision.
the new revision.