User Interfaces

DMD15/DMD15L IBS/IDR Satellite Modem

 

 

Each piece of supported equipment on the control bus executes a Radyne Link Level Task (RLLT) in accordance with its internal hardware and fixed program structure. In a flow control example, the RLLT issues an internal "message in" system call to invoke an I/0 wait condition that persists until the task receives a command from the M & C computer. The RLLT has the option of setting a timeout on the incoming message. Thus, if the equipment does not receive an information/command packet within a given time period, the associated RLLT exits the I/0 wait state and takes appropriate action.

Radyne equipment is logically linked to the control bus via an Internal I/O Processing Task (IOPT) to handle frame sequencing, error checking, and handshaking. The IOPT is essentially a link between the equipment RLLT and the control bus. Each time the M&C computer sends a message packet, the IOPT receives the message and performs error checking. If errors are absent, the IOPT passes the message to the equipment's RLLT. If the IOPT detects errors, it appends error messages to the packet. Whenever an error occurs, the IOPT notes it and discards the message; but it keeps track of the incoming packet. Once the packet is complete, the IOPT conveys the appropriate message to the RLLT and invokes an I/0 wait state (wait for next <SYNC> character).

If the RLLT receives the packetized message from the sender before it times out, it checks for any error messages appended by the IOPT. In the absence of errors, the RLLT processes the received command sent via the transmitted packet and issues a "message out" system call to ultimately acknowledge the received packet. This call generates the response packet conveyed to the sender. If the IOPT sensed errors in the received packet and an RLLT timeout has not occurred, the RLLT causes the equipment to issue the appropriate error message(s) in the pending equipment response frame.

To maintain frame synchronization, the IOPT keeps track of error-laden packets and packets intended for other equipment for the duration of each received packet. Once the packet is complete, the IOPT invokes an I/0 wait state and searches for the next <SYNC> character.

4.9.1.8 RLLP Summary

The RLLP is a simple send-and-wait protocol that automatically re-transmits a packet whenever an error is detected, or when an acknowledgment (response) packet is absent.

During transmission, the protocol wrapper surrounds the actual data to form information packets. Each transmitted packet is subject to time out and frame sequence control parameters, after which the packet sender waits for the receiver to convey its response. Once a receiver verifies that a packet sent to it is in the correct sequence relative to the previously received packet, it computes a local checksum on all information within the packet excluding the <SYNC> character and the <CHECKSUM> fields. If this checksum matches the packet <CHECKSUM>, the receiver processes the packet and responds to the packet sender with a valid response (acknowledgment) packet. If the checksum values do not match, the receiver replies with a negative acknowledgment (NAK) in its response frame.

The response packet is therefore either an acknowledgment that the message was received correctly, or some form of a packetized NAK frame. If the sender receives a valid acknowledgment (response) packet from the receiver, the <FSN> increments and the next packet is transmitted as required by the sender. However, if a NAK response packet is returned the sender re-transmits the original information packet with the same embedded <FSN>.

If an acknowledgment (response) packet or a NAK packet is lost, corrupted, or not issued due to an error and is thereby not returned to the sender, the sender re-transmits the original information packet; but with the same <FSN>. When the intended receiver detects a duplicate packet, the packet is acknowledged with a response packet and internally discarded to preclude undesired repetitive executions. If the M&C computer sends a command packet and the corresponding response packet is lost due to a system or internal error, the computer times out and re-transmits

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Paradyne DMD15L operation manual Rllp Summary
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DMD15, DMD15L specifications

The Paradyne DMD15L and DMD15 are advanced digital modems designed to enhance communication in a variety of networking environments. As part of Paradyne's robust portfolio of networking solutions, these devices are engineered to deliver reliable and efficient data transmission over both copper and fiber optic connections.

One of the main features of the DMD15L and DMD15 is their capability to support Multiple Protocol Data Units (MPDUs), which enables them to handle a diverse range of network protocols seamlessly. This flexibility makes them suitable for different applications, from industrial automation to telecommunications.

These modems utilize advanced modulation techniques, such as Quadrature Amplitude Modulation (QAM), to maximize data throughput while maintaining signal integrity. This ensures that users benefit from high-speed connections, even in challenging signal environments. Furthermore, the DMD15 series incorporates Error Correction Codes (ECC) that enhance data reliability, effectively reducing packet loss and ensuring data coherence during transmission.

The DMD15L is particularly notable for its long-range capabilities, making it a go-to solution for users requiring extended distances without compromising data quality. It features built-in Adaptive Equalization, which automatically adjusts signal levels to optimize performance over varying transmission distances. This technology is crucial in maintaining consistent high-speed connectivity, especially in environments with variable conditions.

Both models are equipped with user-friendly interfaces that facilitate configuration and management. They support SNMP (Simple Network Management Protocol) for real-time network monitoring, allowing administrators to track performance metrics and identify potential issues before they impact users. The devices also include LED indicators for quick status checks, ensuring that users have immediate visibility of operational conditions.

In terms of physical characteristics, the DMD15 and DMD15L are designed for durability and ease of installation. They come in a compact form factor, making them suitable for deployment in constrained spaces. Additionally, their robust casing is built to withstand harsh environmental conditions, making them suitable for both indoor and outdoor installations.

Overall, the Paradyne DMD15L and DMD15 are high-performance modems that combine versatile technologies, reliability, and user-friendly features. They are excellent choices for organizations looking to enhance their communication capabilities and ensure robust data transmission across diverse networks. With their advanced functionalities and adaptability, these modems stand out as key components in modern network infrastructure.
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