Communication ports

The COM ports on OEM7 receivers (except COM1 on the OEM729) are CMOS-level I/O pins only. These ports require the addition of an RS-232 or RS-422 transceiver to provide appropriate signal levels. Most RS-232 or RS-422 transceivers will provide some ESD protection (for harsh environments, additional protection may be required).

A combination of a series ferrite bead and small-value shunt capacitor is recommended on any RS-232/R-S422 lines that leave the enclosure (similar to the arrangement used on the I/O ports and CAN interfaces). Many of the available transceivers provide protection for ESD events to ±15kV – if additional protection is required, an external TVS with a working voltage of ±15V to ±25V will be required.