Multiplexer Driver Developer’s Guide
2.4 Handling of Control Lines on Virtual Ports
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2.4Handling of Control Lines on Virtual Ports
Summary of control line handling.
Table 2: Virtual serial port with Multiplexer Protocol version 2
Signal | Description |
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RING | Read from hardware port, distributed to the first virtual port |
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DCD | Read from hardware port, distributed to the first virtual port |
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DSR | Received with Modem Status Command |
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DTR | Set by user, sent with Modem Status Command, initialized with 1 |
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CTS | Received with Modem Status Command |
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RTS | Set by user, sent with Modem Status Command, initialized with 1 |
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Table 3: Virtual serial port with Multiplexer Protocol version 3 | |
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Signal | Description |
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RING | Received with Modem Status Command |
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DCD | Received with Modem Status Command |
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DSR | Received with Modem Status Command |
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DTR | Set by user, sent with Modem Status Command, initialized with 1 |
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CTS | Received with Modem Status Command |
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RTS | Set by user, Send with Modem Status Command, initialized with 1 |
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2.5Limitation of Virtual Ports
Flow control can be set to RTS/CTS or DSR/DTR. XON/XOFF flow control is not supported. Hardware flow con- trol on the virtual COM ports is handled internally by the Multiplexer Protocol.
The WinMux2k driver handles neither modem nor serenum
The following functions return “success”, but have no effect at all:
•IOCTL_SERIAL_SET_BREAK_ON
•IOCTL_SERIAL_SET_BREAK_OFF
•IOCTL_SERIAL_SET_XOFF
•IOCTL_SERIAL_SET_XON
•IOCTL_SERIAL_RESET_DEVICE
Virtual ports accept any baud rate, though the changed setting will be ignored. Calling the function Open() to a virtual port can take up to 40 seconds. It fails if the module is not connected.
Mux_Drv_DevGuide_v07 | Page 14 of 36 | |
Confidential / Released |
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