Serial port

Applicable receivers: BD940 | BD940-INS

BD940 evaluation board

Item	Description
Port 1 (no flow control)	COM 1 is at 0 - 3.3 V TTL. If the integrator needs this port to be at RS-232 level, a proper transceiver powered by the same 3.3 V that powers the receiver must be added. For development using the I/O board, this COM port is already connected to an RS-232 transceiver. This is labeled COM1 on the I/O board.
Port 2 (with flow control)	COM 2 is at 0 - 3.3 V TTL. This port has RTS/CTS to support hardware flow control. If the integrator needs this port to be at RS-232 level, a proper transceiver powered by the same 3.3 V that powers the receiver must be added. For development using the I/O board, this COM port is already connected to an RS-232 transceiver. This is labeled COM2 on the I/O board.
Port 3 (with flow control)	COM 3 is at 0 - 3.3 V TTL. If the integrator needs this port to be at RS-232 level, a proper transceiver powered by the same 3.3 V that powers the receiver must be added. For development using the I/O board, this COM port uses a USB serial implementation, see the schematic in USB. This is labeled COM3 on the I/O board.
Port 4 (with flow control)	COM 4 is at 0 - 3.3 V TTL. This port has RTS/CTS to support hardware flow control. If the integrator needs this port to be at RS-232 level, a proper transceiver powered by the same 3.3 V that powers the receiver must be added. For development using the I/O board, this COM port uses a USB serial implementation, see the schematic in USB. This is labeled COM4 on the I/O board.

BD940-INS evaluation board

Item	Description
Port 1 (no flow control)	COM 1 is already at RS-232 level and already has 8 kV contact discharge/15 kV air gap discharge ESD protection. This is labeled Port 3 on the I/O board.
Port 2 (with flow control)	COM 2 is at 0 - 3.3 V TTL. This port has RTS/CTS to support hardware flow control. If the integrator needs this port to be at RS-232 level, a proper transceiver powered by the same 3.3 V that powers the receiver must be added. For development using the I/O board, this COM port is already connected to an RS-232 transceiver. This is labeled UHF Port 2 on the I/O board.

Item

Description

Port 1
(no flow control)

COM 1 is already at RS-232 level and already has 8 kV contact discharge/15 kV air gap discharge ESD protection. This is labeled Port 3 on the I/O board.

Port 2
(with flow control)

COM 2 is at 0 - 3.3 V TTL. This port has RTS/CTS to support hardware flow control. If the integrator needs this port to be at RS-232 level, a proper transceiver powered by the same 3.3 V that powers the receiver must be added.

For development using the I/O board, this COM port is already connected to an RS-232 transceiver. This is labeled UHF Port 2 on the I/O board.