ZyXEL ACCESSING INTERNET & INTRANET omni series Instrukcja Użytkownika Pobierz pdf (Strona 42)

30 ISDN Communication Basics

• V.110

• X.75

or the call may be initiated by an analog device (non-data).

This section will provide some general guidelines for setting up the

device for call answer handling. Be aware that the TA will not

automatically answer a call unless S-register S0 is set to a value

greater than 0 (zero). If S-register S0=0, the TA will only report

“RING” to your terminal program. It can also respond with an

audible tone (external) that will allow you to decide whether or not

you should take any action.

When an ISDN data call comes in, the TA will try to negotiate a

connection using the proper ISDN protocol.

When an analog call comes in, the TA will send the call to the analog

port as the factory default, Phone 1 and then Phone 2 (non-data).

Digital Data

The omni currently supports Circuit Switched Data (CSD) for ISDN

data applications. The CSD protocols supported by the TA include:

PPP, MPPP, V.120, X.75, and V.110. PPP is the most popular

protocol used in North America; it is used by most Internet service

providers. Once the TA answers a call, it will examine the incoming

data to determine which protocol to use, and automatically switch to

this mode. The TA is able to auto-switch for PPP, MPPP, V.120,

X.75, V.110, and above protocols over the speech channel. In most

cases, you can rely on the auto-switching feature for your

applications. If you need more specific settings for answering calls,

refer to the section entitled “Answering a Call using MSN” found

later in this chapter.

Determining the Packet Length

The user’s information is sent on a frame-by-frame basis for V.120

and X.75. Sometimes we call it “packetized.” The maximum frame

length on the sending side should not exceed the maximum frame

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ZyXEL ACCESSING INTERNET & INTRANET omni series Instrukcja Użytkownika Strona 42