ZyXEL Communications omni.net LCD+M User Manual

 

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The 40 phone numbers stored in the NVRAM can also be used to place a bundled call with V.120 or X.75, by 
using the [ATDSn] command: 

Dial the (n)th phone number twice for both bundle connections. 

Dial the (n)th phone number for the first connection and dial the (n+1)th phone 
number for the second connection. 

Dial the (n)th phone number for the first connection and the (m)th phone number for 
the second connection. 

For example, 

ATDIS0+S1<Enter>

 will dial the number stored in location ‘1’, and the number 

stored in location ‘2’ for the bundle connection. 

Table 51. AT Command for Dialing Pre-stored Phone Numbers

 

The following AT commands are used to switch the V.42bis data compression on or off for ISDN 
data calls when using X.75 or V.120 protocols: 

Enable V.42bis on V.120 and X.75 ISDN call. 

Disable V.42bis on V.120 and X.75 ISDN call. 

Table 52. V.42bis AT Command

If both sites have set [AT&K44] to enable V.42bis negotiation then XID frames will be exchanged 

through the main B-channel which corresponds to the call established by the first SETUP message. 

Only one data compression channel will be used in bundle connections. That means the 

compression is done before packet disassembly and the decompression is done after packet 

assembly. 

The compression ratio of V.42bis is commonly recognized as up to 4:1 for text files. If the line 

speed is 128Kbps, then the DTE speed may reach 512Kbps. This makes the DTE's normal RS-232