Farallon Communications 612 - Manual (Page 74)

5-10 Netopia ISDN Modem User’s Guide
B Channels
The B Channels area lets you select options for your two ISDN
B channels.
Data Rate. Choose the B-channel data rate you want from the Data
Rate pop-up menu. The data rate options are 56 Kbps and 64 Kbps
(the two data rates ISDN suppor ts). Not all telephone ser vices
suppor t the 64 Kbps data rate. Select the data rate used by your
telephone company.
Protocol. The Protocol pop-up menu lets you choose the transpor t
protocol you want. The protocol options are QuickSelect,
Async/Sync PPP Conver t, and V.120. In most cases, you should use
the QuickSelect protocol. QuickSelect allows the Netopia ISDN
Modem to automatically detect the protocol in use on the ISDN line
and adapt to that protocol. Also, when QuickSelect is active, the
modem conver ts asynchronous Point-to-Point (PPP) information into
synchronous (HDLC-based) PPP information. If you select either the
Async/Sync PPP Conver t or V.120 protocol, the Netopia ISDN
Modem will only use the selected protocol.
Enable Compression. (This option is only available for the Netopia
ISDN Modem Model 412.) Check the Enable Compression box to
turn on data compression. Data 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. To take advantage of data compression, the device you are
dialing into must also suppor t data compression. Note that the
Netopia ISDN Modem’s data compression will not be used if data
compression is in use in your communications application. For more
information about data compression,
see the “Using data
compression” section on page 6-3.
V.120 Max Frame Size. The V.120 Max Frame Size pop-up menu
lets you specify the maximum number of bytes in a V.120 frame.
V.120 is an alternative transpor t protocol to PPP. The available
frame sizes range from 240 to 256 bytes. Leave this set at 256
unless your system administrator or Internet Ser vice Provider (ISP)
instructs you to specify a different value.