Specifications

Loopback
A command like crossConnect(DS_UART0, DS_UART0) will setup an automatic loopback.
Incoming characters will automatically be sent back out the same interface.
Crossover
A command like crossConnect(DS_UART0, DS_UART1) will send characters received on
UART0 out UART1, and characters received on UART1 out UART0.
Wireless Serial
As mentioned previously, a command of: crossConnect(DS_UART0, DS_TRANSPARENT)
will send characters received on UART0 Over The Air (OTA).
Where the data will actually be sent is controlled by other SNAPpy built-ins. Refer to the API section
on the ucastSerial() and mcastSerial() functions.
Local Terminal
A command like crossConnect(DS_UART0, DS_STDIO) will send characters received on
UART0 to your SNAPpy script for processing. The characters will be reported to your script via your
specified HOOK_STDIN handler. Any text “printed” (using the print statement) will be sent out that
same serial port.
This makes it possible to implement applications like a Command Line Interface.
Remote Terminal
A command like crossConnect(DS_TRANSPARENT, DS_STDIO) will send characters received
wirelessly to your SNAPpy script for processing. Characters “printed” by your SNAPpy script will be
sent back out over the air.
This is often used in conjunction with a crossConnect(DS_UARTx, DS_TRANSPARENT) in some
other SNAP Node.
Packet Serial
The last column of the table shows the effect of various combinations using DS_PACKET_SERIAL.
A command like
crossConnect(DS_UART0, DS_PACKET_SERIAL) will configure the unit to
talk Synapse’s Packet Serial protocol over UART0. This enables RS-232 connection to a PC running
Portal, or SNAPconnect.
It also allows serial connection to another SNAP Node, if the appropriate “cross-over” cable is used.
This allows “bridging” of separate SNAP Networks (networks that are on different channels and/or
Network IDs).
A command like crossConnect(DS_UART1, DS_PACKET_SERIAL) will configure the unit to
talk Synapse’s Packet Serial protocol over UART1. On some SNAP Nodes, one UART will be a true
RS-232 serial connection, and the other will be a USB serial connection.
SNAP Reference Manual Document Number 600-0007K Page 29 of 202