1. Introduction With the rapid development of IP technology, the concept of "Everything over IP" has become deeply ingrained. How to effectively connect physically distributed serial devices to the Internet to achieve IP-based telemetry and control has become a hot topic in current research and application. This paper proposes a high-performance communication server solution suitable for connecting serial devices of various speeds to IP networks, using the embedded real-time operating system VxWorks and the high-performance embedded microprocessor MPC860T as the hardware and software platform. It fully leverages the real-time performance of the VxWorks operating system and the excellent network and communication performance of the MPC860T embedded microprocessor. This communication server can connect not only low-speed serial devices to the Internet, but also high-speed serial devices with high real-time requirements. 2. Architecture of the Serial Communication Server In practical applications, various monitoring and control devices often communicate with the outside world via serial communication. Serial devices vary greatly, especially in terms of data transmission rates and formats: some use UART (universal asynchronous receiver transmitter) for low-speed data transmission, while others use HDLC (high-level data link control) and other protocols for high-speed data transmission. Their real-time requirements also differ significantly: some require non-real-time serial data transmission, while others demand strict real-time performance, such as audio, video, and real-time monitoring data from high-speed devices. How can we effectively and reasonably connect various serial devices to IP networks to achieve distributed remote monitoring based on the Internet? This paper proposes a serial communication server architecture, as shown in Figure 1, to address this need. This server effectively connects various serial devices to IP networks and exhibits outstanding real-time performance: it can quickly connect various high-speed, real-time audio and video data to the IP network to achieve IP-based telemetry and control. Figure 1 shows the serial communication server architecture. In this architecture, the server configuration program provides a client/server (C/S) based interface for configuring server communication parameters. Users can use the client configuration program running on a personal computer to communicate with the server's configuration serial port to change communication parameters at any time. The embedded real-time operating system primarily handles real-time task scheduling, interrupt management, and system resource management. The BSP (Board Support Package) is a low-level program written for the specific hardware platform of the communication server. It depends on the hardware and mainly includes initialization code and some driver programs. The FEC (Fast Ethernet Controller) driver provides a 100/10M adaptive Ethernet controller driver. A dual-core embedded microprocessor runs the operating system, application programs, configuration program, and the low-level microcode of the communication protocol. The peripheral interface layer provides various standard communication interfaces, such as RS-232 and RJ-45. 3. Hardware Implementation of the Serial Communication Server In a serial communication server, the performance of the embedded microprocessor is undoubtedly a key factor affecting the overall performance of the server. Based on the communication server architecture shown in Figure 1, this paper selects the FREESCALE dual-core embedded microprocessor MPC860T. It is a microprocessor integrating a dual core and rich peripheral devices, widely applicable in various control fields, especially exhibiting excellent performance in communication and networking. Its composition is shown in Figure 2. The MPC8xx core, based on the PowerPC architecture, is mainly responsible for the operation of the operating system and applications. The CPM module has an independent RISC-based communication processor, which mainly provides services for communication channels such as SCC (Serial Communications Controllers) and SMC (Serial Management Controllers), executes the low-level code of the communication protocol, and controls DMA. The SIU is mainly responsible for system startup, initialization, interrupts, and external bus functions. The FEC provides 10/100M Ethernet control functions, offering independent FIFO and burst DMA, thus providing a 10/100M Ethernet connection without affecting the performance of the CPM. Four SCC channels can be independently configured in HDLC mode, asynchronous HDLC mode, 10M Ethernet mode, etc.; two SMC channels can be configured in UART mode, transparent transmission mode, etc. Figure 2 shows the block diagram of the embedded microprocessor MPC860T. In practical applications, UART and HDLC protocols are two commonly used serial communication protocols, and HDLC is the basis for many other protocols (such as SDLC, SS#7, etc.). Therefore, this communication server uses HDLC and UART as its serial port protocols. The hardware composition of the MPC860T-based serial communication server is shown in Figure 3. In this serial communication server, the four SCC channels operate independently in full-duplex HDLC mode to provide high-speed real-time serial data transmission and quick Ethernet access; the two SMC channels operate independently in UART mode to provide low-speed data communication. SMC1 provides a serial port for system-level and task-level debugging. Users can use SMC1 to configure relevant server parameters through programs running on a personal computer. SMC2 provides low-speed serial communication. The FEC interface provides a full-duplex 100/10M Ethernet access port; 4M Flash is used to store the operating system, user applications, server configuration programs, etc.; 32M SDRAM is used to run applications and store data during operation. The BDM port is used for software and hardware simulation debugging. VisionProbe can be used to debug software and hardware through the BDM port. Figure 3 shows the block diagram of the serial communication server. 4. Software Implementation of the Serial Communication Server In the serial communication server, the operating system is another key factor affecting the overall performance of the communication server. Based on the architecture shown in Figure 1 and the microprocessor used, this paper selects VxWorks, an embedded real-time operating system from Wind River Systems, Inc. VxWorks is a real-time operating system launched by Wind River Systems, Inc. Its modular construction and high customizability enable it to run efficiently and stably in a small storage space, making it very suitable for the development of various high-performance, multi-tasking embedded real-time systems and widely used in communications, aerospace, and other fields. The VxWorks system mainly consists of the Wind kernel, I/O system, BSP, and network protocol stack. The hierarchical structure of the serial communication server software system built based on the VxWorks operating system is shown in Figure 4. In this software system, from bottom to top, there are: a BSP (including UART driver, HDLC driver, config.h configuration file, makefile compilation rule file, etc.) dependent on the communication server hardware system; an Ethernet driver; a hardware-independent operating system layer; and a general server configuration program belonging to the application layer. The operating system layer is provided by VxWorks, while the server configuration program and BSP need to be implemented according to the specific system hardware. The FEC driver needs to be integrated into the entire software system as part of the BSP. The FEC driver is listed separately because it is generic and only needs to be integrated into the BSP. The following mainly discusses the implementation scheme of the BSP and server configuration software. Figure 4 Serial Communication Server Software System 4.1 Communication Server BSP Design and Implementation In embedded systems, BSPs are generally designed and implemented with reference to a rigorously tested BSP with similar functionality. The serial communication server BSP is implemented with reference to the BSP of the ADS860 evaluation board. Based on the architecture and hardware implementation of the serial communication server, the following tasks are required for BSP implementation: Configure the SCC1~SCC4 channels of the MPC860T to HDLC mode, implement the HDLC driver, and connect it to the VxWorks TTY system; Create the sysSccSerial.c file to support the HDLC driver mode; Modify the usrconfig.c or usrSerial.c file as needed to make the HDLC channel a standard I/O device; Modify files such as config.h, configNet.h, makefile, and apc860.h to ensure that the relevant configuration parameters meet the specific requirements of the serial communication server, removing support for 10M Ethernet and adding support for 100/10M FEC Ethernet; The implementation of the HDLC driver is a crucial part of BSP development because the HDLC driver for the SCCx channels needs to meet high-speed and high-real-time requirements, and its performance directly determines the performance of the entire communication server. 4.2 Communication Service Configuration Software Design and Implementation The serial communication server configuration software is an application provided for users to set the communication parameters of the communication server in real time. It is built on a client/server (C/S) architecture, consisting of server-side configuration software running on a serial communication server and client software running on the user's personal computer. They communicate via the computer's serial port and the SMC1 serial port of the communication server. The communication parameters of the communication server mainly include the UART protocol parameters of the SMC2 and the HDLC protocol parameters of the SCCx. 5. Conclusion The serial communication server designed and implemented using the VxWorks real-time operating system and the MPC860T embedded microprocessor is stable, easy to configure, and has excellent real-time performance. It can well meet the requirements of various serial devices accessing the Internet, and is particularly suitable for serial devices with high data transmission rate and real-time requirements. Using the serial communication server, various serial devices can be easily connected to IP networks, thereby realizing remote real-time monitoring and control based on the Internet.