User's Guide for ZyXEL Omni 56K USB Modem

Software XON/XOFF Flow Control

This is a bi-directional flow control. XON and XOFF (flow control protocols for asynchronous communication) character defaults are decimals 17 and 19.These can be changed by modifying the S-Registers S31 and S32.Both the modem and the DTE treats XOFF as a signal to stop transmitting data and treats XON as a signal to restart sending data. Modems does not send these characters received from the local DTE to the remote modem.

Error Control

Error control keeps the modem data link error-free by detecting and re-transmitting erroneous data. Omni 56K USB modem supports both MNP and V.42 error control protocols. The MNP protocol was an industry standard developed and licensed by Microcom, Inc. Omni 56K USB modem supports level 4 and 3 error control protocols, commonly denoted as MNP4 and MNP3.

V.42 is a developed standard by CCITT (Consultative Committee for International Telephony and Telegraphy). V.42 supports both LAPM (Link Access Procedure for Modems) and MNP4. A V.42 handshaking tries an LAPM connection first, and if not successful, it tries MNP4.

Data Compression

In the modem, the data compression is activated in an attempt to reduce the number of bits actually sent. The receiving modem applies these techniques in reverse to recover the actual data from the compressed data stream.

Omni 56K USB modem supports both V.42bis and MNP5 data compression protocols. Data compression needs an error-free data link to work correctly, otherwise the corrupted compressed data stream ruins the decompression process. MNP5 is used with MNP4 error control and V.42bis is used with V.42 error control. The compression efficiency of V.42bis is generally higher than that of MNP5. In some cases, V.42bis can be 50% to 100% higher and in other cases it is just slightly higher. In general, it is about 50% more efficient.

Repeat Dial

The modem dials the default number stored in non-volatile RAM (Random Access Memory), EEPROM (electrically erasable programmable read-only memory) repeatedly if not connected. (s38.0=1,*Dn)

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ZyXEL Communications 56K manual Software XON/XOFF Flow Control, Error Control, Data Compression, Repeat Dial
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56K specifications

ZyXEL Communications has long been a key player in networking technologies, and their 56K modems stand out as a testament to the company’s commitment to high-performance connectivity. The ZyXEL 56K modem provides users with efficient dial-up internet service, delivering reliable performance for both home and small office environments.

One of the main features of the ZyXEL 56K modem is its data transfer capability, offering speeds of up to 56 Kbps. This speed is accomplished by utilizing the latest advancements in modem technology, enabling users to experience smoother browsing, faster downloads, and efficient email communications. Despite being primarily a legacy technology, the ZyXEL 56K modem continues to be valued in areas where broadband connectivity options are limited or unavailable.

The ZyXEL 56K modem utilizes V.90 and V.92 standards—these protocols define how data is transferred over phone lines. With the V.90 standard, the modem can achieve a maximum download speed of 56 Kbps while upload speeds can reach up to 33.6 Kbps with the V.92 standard. V.92 also introduces enhanced features such as a modem on hold, enabling users to receive voice calls while connected to the internet.

In terms of characteristics, the ZyXEL 56K modem is designed with user experience in mind. Its compact, lightweight design allows easy installation and placement, making it ideal for both home users and professionals. The intuitive user interface, coupled with straightforward installation procedures, ensures that even those with minimal technical knowledge can set up the device without hassle.

Additionally, the ZyXEL 56K modem supports various connectivity options, including serial and USB interfaces, allowing compatibility with a wide range of computers and operating systems. This versatility ensures that users can seamlessly connect to their existing devices, enabling broad usage opportunities.

The modem also features built-in error correction and data compression techniques, which improve data integrity and optimize transmission speeds. Overall, the ZyXEL Communications 56K modem remains a reliable choice for users who require dependable dial-up internet access, showcasing the brand's dedication to fostering connectivity in diverse environments.
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