Communication solutions for power utilities
1U SHELF TYPE MAS-2
WITH ASYNCHRONOUS PROGRAMMABLE MODEM MAFP - Rev. 9 (January 2018)
22/39
In order to carry out the data loop, microswitch 5 should be in the ON position. The LEDs
TEST and DATA LOOP on the front plate of the terminal light up to indicate this situation,
both being amber.
2.4.3
Continuous sending of test signals
Should no data terminal equipment be available during commissioning to carry out tests on
the link, continuous sending of a logical level "1", "0" or alternate sequence of "0" and "1" is
possible by means of microswitches 9 and 10 on the front plate. This situation is indicated
on the front plate of the terminal by means of the lighting up of the TEST LED.
It is not necessary the activation of the RTS signal in order to continuously send test signals.
2.5
MODEM BLOCKING
Data reception remains blocked in the following cases:
Loss of carrier in reception, that is to say, when the level of the received carrier falls below
the general alarm threshold.
When microswitch 8 of CONFIGURATION is in ON position.
In half-duplex operation, when the modem is transmitting.
In point-to-multipoint systems without level regeneration it is possible that the reception
levels of the different remote points may differ. In order for the system to function correctly in
these conditions, modem blocking must be avoided when a signal is being received in the
furthest remote points. The receiver adjustment must be carried out taking into account the
weakest signal to be received.