Technical Reference for ZyXEL omni.net series

Data will be transmitted only when the link is in the open phase. Negotiation details are described in RFC1661.

Feature ListAsync to Sync Conversion

PPPuses HDLC-like framing as encapsulation, which can be bit-oriented or character-oriented. Most ISDN routers use bit-oriented HDLC framing, also known as synchronous transmission. However, serial transmission in most personal computers is still character-oriented, also known as asynchronous transmission. In order for an ISDN router and PC to communicate, it is necessary to do asynchronous to synchronous conversion. The omni.net can be used as a bridge. Any data from a PC to a ZyXEL Omni TA will be converted from asynchronous to synchronous form and vice versa.

PPP HDLC framing is described in RFC1662. PPP over ISDN is described in RFC1618.

 

Related AT Command

 

 

Description

 

ATB40

 

Async to Sync PPP Conversion

 

 

 

 

 

 

 

Table 35. Related AT Command for Async to Sync Conversion

Authentication Conversion

After a link is established, it is necessary to authenticate the peer for security reasons. There are two popular authentication methods. One is Password Authentication Protocol (PAP) and the other is Challenge Handshake Authentication Protocol (CHAP). PAP is less secure because it transmits the username/password in plain text form. Unlike PAP, CHAP transmits the username/password in coded form. Some ISPs may support CHAP as the only method for authentication.

For those applications that do not support CHAP, the omni.net converts PAP into CHAP. By default, the PAP/CHAP conversion is always activated, so the authentication from the ISDN TA to PC is always PAP. That means you must configure your software to accept plain text as password authentication. Do not worry about password leakage, the omni.net TA will send the password out

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