Extended Distinctive Ring (EDR)

Extended Distinctive Ring (EDR) is a special feature designed for single telephone line home use to receive fax or data calls without interfering with regular voice calls. When most users install a fax/modem at home, they won’t subscribe to an extra telephone line for occasional fax or data calls; however, fax/data calls do come in from time to time.

If a user lets the fax/data software application answer, voice calls will be missed. On the other hand, if the user or an answering machine answers, fax or data calls may either be missed or the person who answers the call has to go through some procedure to get this call connected to the proper application. Either way is not desirable.

Once enabled with the proper settings, EDR can:

1.Detect the data/fax CNG tone without physically answering the call. After a CNG tone is detected, the modem will report RING or RING n to the application software. The software can cause the modem to answer the call.

2.Detect several DTMF tones without physically answering the call. The DTMF tones, once detected by the modem, will be reported as RING or RING n to the software application.

With these two functions, your modem can be installed with an answering machine or voice telephone set at home. In most cases, the modem should not be set to answer regular rings, nor to report them. Thus, the software will not instruct the modem to answer the call when the phone rings. When a call comes in, the answering machine will answer the phone and play a voice message. At this moment, the modem, having detected the ring signal is gone, will start to listen to the line for CNG tone or DTMF tones.

If the remote caller is an unattended fax machine, it will send a CNG tone for a period of time. The modem will detect the CNG tone and

Special Functions 59

Page 72 Page 74
Page 73
Image 73
ZyXEL Communications U-336SA user manual Extended Distinctive Ring EDR
Page 72 Page 74

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.
Top Page Image Contents