Command

bit

dec

hex

Function and description

Ref.

 

 

16

10

CD tracks presence of data

&C1

 

 

 

 

carrier (see also S38.3)

 

 

5

0

0

CTS Follows RTS in

&R0

 

 

 

 

synchronous mode. Response

 

 

 

 

 

delay set in S26

 

 

 

32

20

Ignore RTS (CTS always ON)

&D2

 

 

 

 

in synchronous mode. (Default)

 

 

6-7

0

0

Assume DTR always On

&D0

 

 

64

40

108.1, DTR OFF-ON transition

&D1

 

 

 

 

causes dial of the default number

 

 

 

128

80

108.2 Data Terminal Ready,

&D2

 

 

 

 

DTR OFF causes the modem to

 

 

 

 

 

hang up and return to command

 

 

 

 

 

state

 

 

 

192

C0

108.2, DTR OFF causes the

&D3

 

 

 

 

modem to hang up and reset the

 

 

 

 

 

modem to profile 0 after DTR

 

 

 

 

 

dropped

 

S23=

bit

dec

hex

Bit mapped register

+105

 

0

0

0

Command echo disabled

E0

 

 

1

1

Command echo enabled

E1

 

1

0

0

Tone dial. (Default)

T

 

 

2

2

Tone dial.

P

 

2

0

0

Pulse dial make/break ratio =

&P0

 

 

 

 

39% / 61%

 

 

 

4

4

Pulse dial make/break ratio =

&P1

 

 

 

 

33% / 67% (Default)

 

 

3-5

0

0

ATX0 (See result code table)

X0

 

 

8

8

ATX1

X1

 

 

16

10

ATX2

X2

Status Registers & Result Codes 111

Page 125
Image 125
ZyXEL Communications U-336SA user manual ATX1 ATX2

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.