HORNER HE200WCM910 User Manual page 37

RS‐232/485 RF Modem Product Manual – MAN0782‐02
FT (Flow Control Threshold) Command
GD (Receive Good Count) Command
HP (Hopping Channel) Command
HT (Time before Wake-up Initializer) Command
<Serial Interfacing> Set/Read the flow control
threshold. When FT bytes have accumulated in
the DI buffer, is de-asserted or the XOFF
software flow control character is transmitted.
<Diagnostics> Set/Read the count of good
received RF packets. Parameter value is reset to
0 after every reset and is not non-volatile (Value
does not persist in the modem's memory after a
power-up sequence). Once the "Receive Good
Count" reaches its maximum value (up to
0xFFFF), it remains at its maximum count value
until the maximum count value is manually changed or the modem is reset.
The GD parameter is not reset by pin, serial port or cyclic sleep modes.
<Networking & Security> HP Command is used to
set/read the modem's hopping channel number.
A channel is one of three layers of addressing
available to the RS-232/485 Modem.
In order for modems to communicate with each
other, the modems must have the same channel
number since each channel uses a different
hopping sequence. Different channels can be
used to prevent modems in one network from listening to transmissions of another.
<Sleep (Low Power)> Set/read time of inactivity
(no serial or RF data is sent or received) before a
wake-up initializer is sent by a TX modem. HT
should be set shorter than inactivity timeout [ST
Command] time of any RX modems operating in
Cyclic Sleep (SM=4-8). The wake-up initializer
sent by the TX modem instructs all RX modems
to remain awake to receive RF data.
From the RX modem perspective: After HT time
elapses and the inactivity timeout [ST Command]
is met, the RX modem goes into cyclic sleep. In
cyclic sleep, the RX modem wakes once per sleep interval [SM Command] to check for a wake-up
initializer. When a wake-up initializer is detected, the modem stays awake to receive data. The
wake-up initializer must be longer than the cyclic sleep interval to ensure that sleeping modems
detect incoming data.
When HT time elapses, the TX modem knows it needs to send a wake-up Initializer for all RX
modems to remain awake and receive the next transmission.
AT Command: ATFT
Binary Command: 0x24 (36 decimal)
Parameter Range: 0 – (Receive buffer size
minus 0x11 bytes)
Default Parameter Value: DO Buffer size minus
0x11 (decimal 17)
Number of bytes returned: 2
AT Command: ATGD
Binary Command: 0x10 (16 decimal)
Parameter Range: 0 – 0xFFFF
Default Parameter Value: 0
Number of bytes returned: 2
Related Commands: ER (Receive Error Count)
AT Command: ATHP
Binary Command: 0x11 (17 decimal)
Parameter Range: 0 – 9
Default Parameter Value: 0
Number of bytes returned: 1
Related Commands: ID (Modem VID), DT
(Destination Address), MK (Address Mask)
AT Command: ATHT
Binary Command: 0x03 (3 decimal)
Parameter Range: 0 – 0xFFFF
Default Parameter Value: 0xFFFF (wake-up
initializer will not be sent)
Number of bytes returned: 2
Related Commands: LH (Wake-up Initializer
Timer), SM (Sleep Mode), ST (Time before
Sleep)
[x 100 milliseconds]
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