General
Number of serial ports	8 Stück
Data bits	5, 6, 7, 8 -
Stop bits	1, 1.5, 2 -
RS-485 resistors	1 kΩ / 150 kΩ Ω
RS-485 terminator	120 Ω
Auto MDI/MDI-X	ja -
Air humidity	5–95 % (nicht kondensierend)
Dimensions with mounting bracket	480 × 195 × 44 mm

The Moxa NPort 6650-8 12-48V is an industrial 8-port terminal server that connects serial RS-232/422/485 devices over Ethernet networks. The device serves as a bridge between legacy serial devices and modern IP-based networks, enabling integration into existing systems such as SCADA, power distribution, or telecommunications installations. The Serial Interface provides eight 8-pin RJ45 connectors, which can be configured as needed for RS-232, RS-422, or RS-485. Support for baud rates from 50 bps to 921.6 kbps, including non-standard values, along with flexible settings for data bits, stop bits, parity, and flow control (RTS/CTS, DTR/DSR, XON/XOFF), ensures high adaptability to various serial end devices. Data direction control is handled automatically via ADDC (Automatic Data Direction Control), which is particularly advantageous for RS-485 applications.

Applications include industrial automation, remote control systems, monitoring systems, and infrastructure networks, where reliable, secure, and maintenance-friendly communication between serial devices and Ethernet networks is required. The Compatibility with a wide range of operating systems, including Windows (95 to 11, Server 2003 to 2022, Embedded CE, XP Embedded), Linux (kernel 2.4.x to 6.x), macOS (10.12 to 11.x), as well as various Unix and ARM platforms, enables flexible integration into heterogeneous IT environments. VM support for VMware ESXi, Fusion, and Parallels, as well as Android support from version 3.1.x, expands the range of applications.

The Technology explained simply shows that the terminal server features an integrated Ethernet interface with a 10/100BaseT(X) RJ45 port, supporting Auto MDI/MDI-X and equipped with magnetic isolation of 1.5 kV. This protects the device from transient voltage spikes and enables a robust network connection. The Security features include authentication via local database, RADIUS, or TACACS+, encryption with AES-128/256, HMAC, RSA-1024, SHA-1/256/384, and protocols such as HTTPS (TLS 1.2), SNMPv3, and SSHv2. These measures protect data transmission from unauthorized access and manipulation.

The Software functions offer multiple configuration options: Web Console (HTTP/HTTPS), Windows Utility, DSU, MCC Tool, serial configuration, Telnet/SSH. Supported network protocols include ARP, BOOTP, DHCP, DNS, HTTP, ICMP, IPv4/IPv6, LLDP, PPPOE, SMTP, SNMPv1/v2c/v3, SNTP, TCP/IP, Telnet, UDP. Routing is possible via RIPV1/V2 and static routes. Time management is handled via SNTP client, and MIB-II is supported. The Expandability through NM modules (RJ45 or fiber) allows flexible adaptation of network connections.

The Power supply is provided via a ±48 VDC input, with an operating voltage range of 20 to 72 VDC (positive) and -20 to -72 VDC (negative). The current consumption is 293 mA at 48 VDC. The device features an integrated LCD display and buttons for local operation, simplifying configuration and diagnostics on-site. A configurable alarm output with 1 A @ 24 VDC (resistive load), along with an integrated watchdog timer and alarm functions (buzzer, RTC), enhances system reliability.

The Mechanics of the device include a metal housing designed for rack mounting. Dimensions are 480 × 195 × 44 mm (with bracket) or 440 × 195 × 44 mm (without bracket), and the weight is 3,460 g. The Environmental conditions are designed for industrial use: operating temperature from 0 to 55 °C, storage temperature from -40 to 75 °C, humidity from 5–95 % (non-condensing). The Certifications include EMC (EN 55032/35), EMI (CISPR 32, FCC Part 15B Class A), EMS (IEC 61000-4-2/-3/-4/-5/-6/-8), Safety (UL 60950-1), Transportation (NEMA TS2), and mechanical durability (Vibration IEC 60068-2-6, Drop IEC 60068-2-34). The Environmental declaration includes RoHS, CRoHS, and WEEE. The MTBF is 636,600 hours according to Telcordia (Bellcore) standard. The warranty is 5 years; further details are available at www.moxa.com/warranty.

The Operational advantages lie in high reliability, simple local operation via LCD and buttons, comprehensive security features, and broad compatibility with various operating systems and network protocols. The integrated isolation and wide voltage range increase robustness in industrial environments. Expandability via NM modules enables a scalable network architecture.