cannot use adaptive rate.

SLAVE

AT&X2

Recovered receiver clock serves as

 

 

transmission clock.

RTS Options

There are two RTS options. The choice depends on application and host/terminal requirements. In asynchronous mode RTS is used as a hardware flow control signal.

IGNORED

AT&R1

RTS is ignored; always assumed

 

 

to be ON. (Default)

CTS TRACKS RTS

AT&R0

Delay before CTS responds to

 

 

RTS's change. The delay is set

 

 

in the S26 register.

Command State Options

For synchronous data communication, there are two options you can choose from to define how the modem will operate in the command state.

SYNC DATA

AT&M1

The modem accepts asynchronous

 

 

commands in command state, but

 

 

exchanges data synchronously in data

 

 

state.

SYNC

AT&M3

The modem accepts synchronous

 

 

command (V.25bis) and exchanges

 

 

data synchronously with a remote

 

 

modem.

Dialing from Synchronous Mode

1.Dial from the terminal using asynchronous commands : Set &M1 and use asynchronous AT commands to dial the number.

44 LCD Panel Operation

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ZyXEL Communications U-336SA user manual RTS Options, Command State Options, Dialing from Synchronous Mode

U-336S, U-336SA specifications

ZyXEL Communications, a leading global provider of networking and cybersecurity solutions, has offered a range of products designed to cater to various connectivity needs. Among these, the U-336SA and U-336S modems stand out for their reliability and performance, particularly in the dial-up category during the heyday of internet access.

The U-336SA and U-336S modems are external devices that revolutionized the way users connected to the internet in the late 1990s and early 2000s. Designed for both home users and small businesses, these modems supported 33.6 Kbps data transfer rates, which, at the time, were considered cutting-edge. This capability allowed for reasonably swift internet browsing, email communication, and file downloads compared to earlier modems.

One notable feature of both the U-336SA and U-336S models is their plug-and-play functionality. This ease of use made them accessible to even the less tech-savvy users, allowing quick and straightforward installation. Users could connect the modems to their PCs or laptops via a standard serial interface, minimizing setup time and complexity.

Additionally, both modems were equipped with error correction and data compression technologies. The V.42 and V.42bis protocols enhanced data integrity during transmission, ensuring that users experienced fewer disruptions and greater reliability in their connecting experience. This was particularly vital for tasks like file transfers and large downloads, where data integrity was paramount.

The modems also featured compatibility with various operating systems, including early versions of Windows, which expanded their appeal to a broader audience. The U-336SA was specifically engineered as a standalone device, while the U-336S could often be used with existing computer systems, showcasing versatility in various deployment scenarios.

In terms of design, both modems were compact and lightweight, allowing for easy portability. This made them suitable for users who required connectivity on the go or in different locations.

Ultimately, the ZyXEL U-336SA and U-336S modems represent a significant technological achievement in the history of internet connectivity. Their introduction set the stage for subsequent advancements in modem technology and played a crucial role in the evolution towards broadband and high-speed internet access that we enjoy today. Their legacy endures in the foundational technologies and protocols that continue to drive modern telecommunications.