Copyright Adcon RF Technology 2002
LC-Ind Modems Technical Manual
Rev: 1.0
Page: 18
4. ADVANCED OPERATION
4.1 Transparent mode
In Transparent Mode, the LC-Ind radio modem behaves like a wired serial link :
I.e. LC-
Ind radio modem does not only transmit to the radio channel every serial link received data, but also
transmits on the serial link the radio channel received information.
Basically, the LC-IND radio modem, as a half-duplex module, reproduces the half-duplex
function of a RS-485 cable.
In Transparent Mode, no frame control is performed by the LC-IND radio modem, neither on
the serial link, nor on the radio link. Flow control must be carried out by software applications via
protocols in use such as MODBUS, JBUS, etc…
Consequently, Transparent Mode does not give any possibility to change the module
parameters without a temporary return to Hayes mode.
NOTE: The user’s software application must adequately verify that all buffers are transmitted
correctly taking into account that an interrupted transmission link may lead to losing one or several
buffers.
The transparent mode does not involve the absence of delay in transmission / reception.
The time for UART reception of the first character to be transmitted must be taken into account as
well as the time for carrier synchronisation preamble, time for radio transmission and time for the
transmission into the UART of the receiver.
The total delay between the character transmission on the serial link of an LC RF-Modem and
the reception of the first character on the serial link of another LC RF-Modem must not exceed 25
ms for a serial link at 9600 Baud.
Priority to transmission
The LC RF-Modem takes priority over the reception of the characters coming from the serial link
connected to it. Thus a permanent reception or jamming on its channel of a radio signal (valid or not)
cannot involve locking to switch to Hayes command.
