8 AT Command Set

Summaries

Basic AT Command Set

Command

Options

Function & Description

Ref.

A/

 

Re-execute the last command once.

 

A>

 

Re-execute the last command once or

 

 

 

repeat the last call up to 9 times. (See

 

 

 

also S8)

 

<any key>

 

Terminate current connection attempt

 

 

 

when enter in handshaking state.

 

+++

 

Escape sequence code, entered in

 

 

 

data state, wait for modem to return

 

 

 

to command state.

 

All the Following Commands Require a “AT” Prefix:

 

 

 

 

 

Command

Options

Function & Description

Ref.

A

 

Go on-line in answer mode. (See also

 

 

 

S39.2, S43.6)

 

Bn

 

Handshake option.

S28.7

 

B0 *

Select CCITT V.22 for 1200 bps

 

 

B1

Select Bell 212A for 1200 bps

 

 

 

communication.

 

Ds

 

Dial s (numbers and options) that

 

 

 

follow (see also S38.0, S35.4). The

 

 

 

options of s are listed as follows:

 

88 AT Command Set Summaries

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ZyXEL Communications U-336S AT Command Set Summaries, Basic AT Command Set, Command Options Function & Description

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.