Farallon Communications 412 Manual Do Utilizador

Compression is a method of reducing the size of data without losing 
any of the information. Models 412 and 612 of the Netopia ISDN 
Modem automatically use Stac data compression to compress data 
to improve data transfer times. 

The following check modes are negotiable: None, One Byte 
Sequence Number, and Extended. The mode is automatically 
negotiated when a PPP call is placed to another device that 
suppor ts the compression control protocol. Generally, Extended is 
the preferred mode. The amount of compression depends on the 
type of file being transferred. For example, a text file compresses 
better than a binar y (application or executable) file.

Compression is enabled by default. If you enable compression on 
the ISDN modem and your application uses compression, 
compression will be disabled in the ISDN modem.

You can use compression in dual B channel Multilink PPP 
connections and single B channel connections. By using 
compression on a single B channel, you can achieve per formance 
rivaling a two B channel connection at a fraction of the cost. 
Because telephone and Internet providers often base charges on 
the number of B channels used, the Netopia ISDN Modem’s 
compression feature, which is not available in most other ISDN 
terminal adapters, lets you achieve nearly the throughput of a two B 
channel connection at the price of a single B channel connection. 

Compression is negotiated between your ISDN modem and the 
device to which you are placing the Multilink PPP call. To take 
advantage of data compression, the device you are dialing into must 
also suppor t data compression. If the other device does not 
suppor t compression, compression will not be implemented.