ZyXEL Communications Omni TA128 - Manual (Page 66)

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Speeds of 128Kbps
BRI ISDN consists of three (2B+D) logical channels. Each B
channel can be used independently for a dial-up connection
running at 56Kbps or 64Kbps (bits per second).
The two B channels can be used together for a single data
connection to provide 112K (with In-Band Signaling) or 128K
(when Out-of-Band Signaling is used). It is called a “Bundle
Connection”.
The type of channel bundling described in the V.120 section is
supported only between the following ZyXEL products: omni.net,
Omni TA128, or Elite 2864I, and uses Multiple Link Protocol
(MLP) and “cFos” channel bundling (CCB).
Identifying your line provisioning
For bundled connections, the two B channels of your ISDN line
must be able to handle data circuit switch connections with
unrestricted 64K or 56Kbps line speeds. Two separate data calls
will be established consecutively.
Making a Bundled Call with V.120
A bundled V.120 connection is initiated at the calling site when
ATB20 (B channel protocol V.120) has been selected and the
channel bundling mode has been enabled by an AT&J3
command. The channel bundling command (AT&J3) must be set
on both the calling and receiving sides, otherwise a single channel
connection will be made.
Type:
ATB20 (Set B channel protocol to V.120)
AT&J3 (Set the TA128 to make a bundled call)
Type:
AT&WZ (If you want to save the setting)