4
The I
2
C adapter implements the RS-232 interface using the following pins:
2.1.1 DB-25 Serial Port Pinout
DB-25 Pin 2, Transmit Data from the Host Computer to the iPort
DB-25 Pin 3, Receive Data from the iPort to the Host Computer.
DB-25 Pin 4, Request to Send from the Host Computer to iPort.
DB-25 Pin 5, Clear to Send from the iPort to the Host Computer.
DB-25 Pin 7, Ground between Host Computer and iPort
2.1.2 DB-9 Serial Port Pinout
DB-9 Pin 3, Transmit Data from the Host Computer to the iPort
DB-9 Pin 2, Receive Data from the iPort to the Host Computer.
DB-9 Pin 7, Request to Send from the Host Computer to iPort.
DB-9 Pin 8, Clear to Send from the iPort to the Host Computer.
DB-9 Pin 5, Ground between Host Computer and iPort
2.2 +5VDC Power Jack
The I
2
C adapter requires 50ma of REGULATED +5 volt power. This power can be
supplied in one of two ways:
• Via the power jack.
If the I
2
C adapter is powered via its +5VDC power jack, excess power is
available via the +5V wire in the I
2
C connector to power external devices.
• Via the I
2
C interface connector.
If 50ma of regulated +5V power is available in the target system, the I
2
C adapter
can be powered via the +5V wire in I
2
C interface connector.
2.3 I
2
C Interface Connector
The I
2
C adapter includes a four wire, positive locking, modular receptacle connector
(see Appendix A) for interfacing to an external I
2
C Bus. Lines provided include I
2
C
Clock (SCL), I
2
C Data (SDA), Ground, and +5VDC.
Use of the +5V wire is optional. Connect this wire to the target system to power the
I
2
C adapter and the target system from a common regulated 5V power supply.
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