Physical Layer

The communication is based on an RS232 connection with these default settings:

  • 115200 baud

  • 8 data bits

  • 1 stop bit

  • Parity None

  • No flow control

The baud rate is configurable when starting the client. If not configured the default value of 115200 baud is used. To set a specific baud rate, use the -b argument.

Example of starting the serial client with 9600 baud:

/usr/bin/RapiSerialClient -c /dev/ttyS0 -b 9600

Note

A lower baud rate may not be sufficient for a flawless communication. Keep in mind when choosing a lower baud rate!

The connector provided on the coffee machine side is a DE-Sub 9 type connector as shown below:

../_images/Payment_RAPI_Connector.svg

Note

The pins 2, 3 and 5 are assigned the usual RxD, TxD and GND function of RS232 connections. However since this connector is also used for CCI/CSI devices, the pin 8 provides a 24V supply voltage (max. 1A) to the payment equipment and pin 9 (usually functioning as Ring Indicator (RI) line) is hardwired to pin 5 - Ground. This should be considered for example when plugging this connector into RS232 socket of a PC. In that case pin 8 should be cut from the cable or disconnected by some other means. All other pins are unused.