Keeping A Line Connection During Idle Time; Answering Async To Sync Ppp Calls; Multilink Ppp; Making A Call Using Multilink Ppp - ZyXEL Communications Omni TA128 User Manual

Chapter 6 - Async to Sync PPP and SLIP

Keeping a Line Connection During Idle Time

If you are using the PPP to access a Server, more often than not, the Server will have a
watchdog timer to monitor the line activity. If the idle time exceeds some time interval
(usually 1 minute), the Server will release the connection for other clients to dial in. As a
user, you could be very annoyed in some circumstances since, once disconnected, you
have to dial to the server again and repeat the login procedure. The value in register S124
(in seconds) is used as the idle time gauge. If the idle time exceeds this guarding period,
the Omni TA128 will send out a dummy PPP packet to the Server to keep it from
disconnecting the line.
Example: If the server you are calling disconnects after 1 minute of inactivity, issue the
following command before connecting:
ATS124=59<Enter> (send dummy PPP packet after 59 sec of inactivity)
Setting S124=0 will disable this function.

Answering Async to Sync PPP calls

There is no need to configure the ISDN mode to the protocol of an incoming call. If it is
set to auto-answer or an answering command is issued, the Omni TA128 will be able to
determine the correct protocol to use by examining the data coming in from the remote
site. One exception to this is when the ISDN data call is carried through a Speech bearer.
In this case you would need to set up an MSN entry for the phone number of the calling
party, so calls from this number will be answered properly. To do this, use
AT&ZI3= xxx; where 'xxx' is the number that the call is expected to come in from.
Please refer to the section entitled "Data over Speech Channel" in Chapter 4 for details.
To allow the Omni TA128 to automatically answer the incoming call, you need to set S0
to a value greater than 0 (i.e. ATS0=1). Omni TA128 will answer the call and use
asynchronous to synchronous conversions to and from the DTE. If S0 is not set (S0=0),
the DCE will report "RING" and will also make an audible ring notification.

Multilink PPP

Multilink PPP (MPPP) is a protocol that allows virtual bundling of the two B channels,
for connection speeds of 128Kbps. MPPP support is a standard feature of Omni TA128
models.

Making a call using Multilink PPP

A Multilink PPP connection is initiated at the calling site when ATB40 (B channel
protocol HDLC PPP) has been selected and the Multilink PPP mode has been enabled by
an AT&J n command:
AT&J0 Disables Multilink PPP
AT&J1 Enables Multilink PPP in answer mode only
AT&J2 Enables Multilink PPP in call mode only
AT&J3 Enables Multilink PPP in both call and answer modes
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