SHORT HAUL MODEM (SHM-FSK)
2.3 Operating Mode
The SHM-FSKs can be operated in either point-to-point or multipoint polling mode.
For multi-drop data communications, the SHM-FSK can be operated with one Master and typically up to eight Remote units. The transmitter in each Remote unit is controlled by the intelligent device it is connected to. The Master unit’s transmitter remains on all the time. The green two-position pluggable terminal block at the receptacle marked “LINE” on the back of the SHM-FSK unit is used with any two-wire cable (does not need to be twisted). Since the FSK signal is AC, there is no polarity required on any of the data- line connections.
2.4 Diagrams
Figure 2-1shows the location of the LEDs on the front of the SHM-FSK.
CD RxD TxD LPBK PWR
Figure 2-1. Location of LEDs on the SHM-FSK.
