Developers' Notes for
IntelliPort III Loadware, Version 2.0.2

Supporting Higher Line Speeds
The Power RackPort supports five line speeds which are not supported on earlier IntelliPort II products:
	153,600
	230,400
	307,200
	460,800
	921,600
Most operating systems will not support these rates in a standard fashion: you will need to use Computone driver-specific features to configure a port to run at any of these rates. The method to use depends on the operating system.
Here are some examples; if your operating system is not mentioned, check the release notes supplied with your IntelliPort III drivers. (Remember, you must install IntelliPort III drivers in order to use the Power RackPort).
Compatibility
UART-Specific Features
The original IntelliPort II and IntelliPort II EX expansion modules use CD1400 UARTS to convert data to and from serial format. IntelliPort III expansion boxes, including the Power RackPort, use ST654 UARTS which offer faster, more robust performance.
There are some features supported by the older UARTS which are not supported by the newer hardware. The new IntelliPort III loadware continues to support these features, when used with original IntelliPort II EX expansion boxes. If you are using IntelliPort III expansion boxes (including the Power RackPort), the loadware ignores the attempt to use this feature.
Most of these features are seldom-used, but are listed here in case you are one of the few that would be affected:
	Split baud rates: This is the capability to configure a single port to transmit and receive at different line speeds. In our UNIX drivers, this has been supported using the inbaud and outbaud IntelliSet profile parameters. When IntelliPort III expansion boxes are used, any attempt to change the receiver or transmitter rate separately will change both rates. If you try to configure a port to use split rates, one of the rates will be used for transmit and receive, but which rate will depend on the particular driver you are using, so you should avoid configuring the newer ports in this way.
	DSR receiver control: This feature prevents incoming data from being recognized unless the DSR data set signal is asserted. In our UNIX drivers, this is supported using the dsrreq IntelliSet profile parameter. When IntelliPort III expansion boxes are used, this configuration will be ignored. Incoming data will be recognized regardless of whether DSR is asserted.
	 RTS Half-Duplex: This feature causes the RTS signal to be automatically asserted whenever the UART contains data to be sent, and negated at other times. In our UNIX drivers, it is supported via the hduplex IntelliSet profile parameter. When IntelliPort III expansion boxes are used, this configuration will be ignored, and RTS will not depend on the transmitter.
Mixing the Old and New
Suppose your installation contains some original IntelliPort II product as well as newer products such as the Power RackPort. Each product has some features not present on the other. What happens if you try to use features that are not present? This ultimately depends on the driver, but in most cases this will not produce a warning or error: the port will be set to the closest configuration it supports.
	If you attempt to set an IntelliPort II port to a line speed higher than 115200, the port will default to 115200. IntelliPort III ports will be set to the correct rate.
	If you attempt to specify split baud rates for an IntelliPort III port, the results depend on the driver. (Any attempt to change one of the rates alone would affect them both, so it depends on which rate the driver sends to the board last.)
In mixed installations, you should record which ports are supported by IntelliPort III products, so to avoid accidently specifying an unsupported configuration.
CAbling
Remember, the Power RackPort uses connectors with a different pinout from original IntelliPort II products. Be sure to read chapter 4, Power RackPort Serial Cables, in order to avoid confusion.
Developer Notes
This section provides the details needed by third-party driver developers to adapt their drivers to provide full IntelliPort III support.
Command compatibility
All commands supported by the IntelliPort II loadware are recognized by IntelliPort III loadware. Any attempt to apply a command to hardware that doesnÕt support the associated feature will we silently ignored.
IntelliPort II loadware had strong restrictions on whether certain commands could be sent in bypass or inline format. These restrictions are eased: all commands can be sent in either format without causing an error condition. Caution: certain commands will not have the desired effect unless they are sent in the mode intended. For example, a start flush command would have no practical effect if sent inline.
The following table lists the specific commands which have changed in some way from the original IntelliPort II implementation, or whose meaning may now depend on the type of expansion boxes being used.
Table 5-1: Command Compatibility				
	
7	Set Baud Rate	Originally, arguments 1-23 selected rates 50-115200 from a table, arguments 24-25 selected 			custom rates. These remain unchanged, but arguments 26-30 are recognized:		
	(IntelliPort II expansion boxes)
			26-30 select 115,200
	(Power RackPort)
			26: 153,600 27: 230,400 28: 307,200 29: 460,800 30: 921,600	

For commands 42, 43, 61, 65, 74, 79, and 88: If the command is applied to an IntelliPort II expansion box port, it is supported in the usual fashion. On a Power RackPort or other ST654-based product, differences are noted.

42	Set Output Baud Rate		
43	Set Input Baud Rate	For commands 42-43, Arguments 26-30 are also supported.
				On Power RackPort ports, each command will change both the output and input rates.
	
61	Set Loopback Mode	Remote Loopback mode (argument 2) is not supported on Power RackPort.	
65	Enable/Disable RTS Half-duplex mode
				RTS Half duplex mode not suppored by Power RackPort	
74	Specify TX burst MAX	This is specific to the CD1400 UART: ignored on Power RackPort.	
79	Transmit Immediate	Supported as before.	Depends on CD1400-specific features: command is ignored.	
88	Receiver timeout/threshold
				This is specific to the CD1400 UART and is ignored on Power RackPort. (Note that
				command 90 is still supported in the same way.)

84	Get Box IDÕs	The status message that is returned reports the type of expansion box being used. IntelliPort III expansion boxes have different ID's to distinguish them from the original IntelliPort II styles.		

91	Send Break (long)	This is a new command: it works just like command 35 (which is still supported) except that the argument specifies the time in 1/10ths of seconds, rather than in milliseconds.		

Other Considerations
The IntelliPort III loadware image is slightly larger than 32K, while the last IntelliPort II loadware released was slightly under this size. Once loaded on the board, the DRAM overhead requirements are actually less than previous versions, so allocated buffer space will be slightly larger.
Under most circumstances, the aggregate throughput of IntelliPort II expansion boxes will be comparable or slightly faster than the older loadware. IntelliPort III expansion boxes should demonstrate about twice the aggregate rate of IntelliPort II boxes under similar conditions.