Multi-Tech MultiModem ISDN MT128ISA-UV, User Manual

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MultiModemISDN User Guide
MT128ISA/PCI
Determining your modem type
Refer to the following information for assistance in selecting the appropriate modem for your
ISDN application.
• The Internet MLPPP protocol is for connecting to Internet Servers and other point-to-point
(PPP) protocol servers using the Multi-Link Point-to-Point protocol. MLPPP is the only
protocol which can link two ISDN B-channels to establish a 128 kilobits per second
bandwidth data path.
Before attempting to make a 128K MLPPP connection, verify that your ISP supports this
feature.
• X.75 protocol is used mostly for BBS access and file transfer, but may be used for Internet
access in some locales.
• The Universal-1 and -2 are multi-purpose modems. In Universal modem mode, the ISDN
driver selects HDLC protocol as the default. You can change to the appropriate protocol
through the ATBn commands (see Chapter 3). The AT command can be issued through
Start>Settings>Control Panel>Modems>ISDN modem>Properties>Connection,
Advanced>Extra settings.
• The Internet PPP protocol is for connecting to Internet and other communications servers at
64 kilobits per second. Only one B-channel is used, leaving the other free (if supplied by
your ISDN service provider) for a different data transfer operation or a voice or fax call.
• BOD means Bandwith on Demand. BOD first establishes a 1B (64K) data channel and
waits until data traffic is over the value specified in ATS53 (see Chapter 3 for more
information about AT commands). When data traffic goes over this default value (or the
value set in the user-specified AT command), BOD establishes a second B channel and
bundles it to a 128K communication link for better performance. BOD allows greater
flexibility in handling voice and data calls simultaneously.
Bandwidth on demand is very useful where ISDN access is charged for by the minute, since
the second B-channel is only used when the volume on the first B-channel has exceeded a
threshold value for a certain period of time.
Before BOD activates all three of the following conditions must be met:
•Average data traffic is lower than the value (ATS53) in a specific period (ATS54)
• User wants to make an outgoing voice call (picks up the handset)
• There is an incoming voice call (ring signal on an analog telephone device)