# Open_Serial hash command

The Open_Serial hash command gives you a convenient way of initialising the serial port without having to manually build Communications Control Blocks (CCB) in NVEM. Open_Serial "takes" one of a number of hash functions, each hash function being specific to a communications protocol.

The first time an Open_Serial hash command is executed in a program, the program will stall until 10 seconds from startup. It is perfectly possible to "re-open" the serial port with different settings, and the behaviour will change immediately.

Example:

# Open_Serial Port(COMTTL) User(38400,8,N)

The above hash command will open the TTL serial port at 38400, with 8 data bits and no parity, and invoke the User protocol. "User protocol" means the port can be used to send and receive any arbitrary data (as distinct from, say, ModBus, which has its own very specific data formats).

The available hash functions are listed in this section.