Product manual
9XTend‐PKG‐R™RS‐232/485RFModem–ProductManualv1.2.4
©2005MaxStream,Inc.ConfidentialandProprietary 30
LH (Wake-up Initializer Timer) Command
AT Command: ATLH
Binary Command: 0x0C (12 decimal)
Parameter Range: 0 – 0xFF
[x 100 milliseconds]
Default Parameter Value: 1
Number of bytes returned: 1
Related Commands: HT (Time before Wake-
up Initializer), SM (Sleep Mode), ST (Time
before Sleep)
<Sleep (Low Power)> LH Command is used to
set/read the duration of time for which the wake-
up initializer is sent. When receiving modems are
put into Cyclic Sleep Mode, they power-down after
a period of inactivity [specified by ST (Time before
Sleep) Command] and will periodically awaken
and listen for transmitted data. In order for the
receiving modems to remain awake, they must
detect ~35ms of the wake-up initializer.
LH Command must be used whenever a receiver is operating in Cyclic Sleep Mode. This lengthens
the Wake-up Initializer to a specific amount of time (in tenths of a second). The Wake-up
Initializer Time must be longer than the cyclic sleep time that is determined by SM (Sleep Mode)
Command. If the wake-up initializer time were less than the Cyclic Sleep interval, the connection
would be at risk of missing the wake-up initializer transmission.
Refer to Figures 4-03 & 4-04 of the SM Command description to view diagrams of correct and
incorrect configurations. The images help visualize the importance that the value of LH be greater
than the value of SM.
MK (Address Mask) Command
<Networking & Security> MK Command is used to
set/read the “Address Mask”. All data packets
contain the Destination Address of the
transmitting modem.
When an RF data packet is received, the
transmitter’s Destination Address is logically
“ANDed” (bitwise) with the Address Mask of the
receiver. The resulting value must match the
Destination Address or the Address Mask of the
receiver for the packet to be received and sent
out the modem’s DO serial port. If the “ANDed” value does not match either the Destination
Address or the Address Mask of the receiver, the packet is discarded. (All “0” values are treated
as “irrelevant” values and are ignored.)
AT Command: ATMK
Binary Command: 0x12 (18 decimal)
Parameter Range: 0 – 0xFFFF
Default Parameter Value: 0xFFFF (65535d)
Destination address (DT parameter) of the
transmitting modem must exactly match the
destination address of the receiving modem.
Number of bytes returned: 2
Related Commands: DT (Destination
Address), HP (Hopping Channel), ID (Modem
VID), MY (Source Address)
MT (Multi-Transmit) Command
<Networking & Security> MT packets do not
request an acknowledgement from receiving
modem(s). MT takes precedence over RR, so if
both MT and RR are non-zero, then MT+1 packets
will be sent, with no ACK requests.
When a receiving modem receives a packet with
remaining forced retransmissions, it calculates the
length of the packet and inhibits transmission for
the amount of time required for all
retransmissions. Thereafter, a random number of delay slots are inserted between 0 and RN
before transmission is allowed from the receiving modem(s). This prevents all listening modems
from transmitting at once upon conclusion of a multiple transmission event (when RN > 0).
AT Command: ATMT
Binary Command: 0x3D (61 decimal)
Parameter Range: 0 – 0xFF
Default Parameter Value: 0 (no forced
retransmissions)
Number of bytes returned: 1
Related Commands: Networking (DT, MK,
MY, RN, TT), Serial Interfacing (BR, PK, RB,
RO), RF Interfacing (FS)
Comment: Actual number of forced transmissions is the parameter value plus one. For example,
if MT=1, two transmissions of each packet will be sent.