Dell Inspiron 1120 Hardware Manual page 23

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Using the modem: Mini PCI Type 3B Data Fax Modem by 3Com User's Guide
Overview • Transferring Data • Faxing
Overview
Your modem allows you to send and receive both data and fax files using your communications software. Your modem can also be used for data
communications with an online service, the Internet, an electronic Bulletin Board System (BBS), or another modem, at up to V.90 speeds.
Your modem can connect at speeds up to 56,000 bits per second (bps), and send or receive faxes at speeds up to 14,400 bps. With V.90
technology, your modem is capable of receiving at up to 56 Kbps and sending at up to 31.2 Kbps. Actual download speeds you experience may
be lower due to varying line conditions. Compatible phone line and server equipment are required.
Your modem supports class 1 faxing. If problems arise when you attempt to fax, we suggest you try changing the fax class.
Transferring Data
Because your modem is optimized for Windows, it takes advantage of the Windows interface and the capabilities of your computer to achieve
faster data transfers than a regular modem.
Terminal Emulation Protocols
You may be required to designate a terminal emulation protocol to use for data transmission. Various computer systems use different types of
terminal emulation, such as IBM 3270, TTY, DEC, or ANSI. Contact the system operator of the host modem you are dialing into to determine the
type of emulation to use for that connection. If the system operator is unknown, try using the ANSI terminal emulation protocol.
File Transfer Protocols
File transfer is the ability to transport files between two computers via two modems. The modem must use a file transfer protocol (ftp), which can
correct errors in transmission and begin the file transfer process. Both modems must use the same file transfer protocol.
At the time you set up a file transfer, your communications software will prompt you to designate a file transfer protocol. The following table
describes some of the most common protocols:
Protocol Description
ZMODEM Transfers files in a streaming protocol, making it very fast even with error correction. Also provides an automatic receive function
that saves you steps when receiving data.
YMODEM- A variation of YMODEM designed for modems that support error control. Does not provide error correction or recovery, but relies
on the modem to provide it. If any block is unsuccessfully transferred, the entire transfer is canceled.
G
YMODEM An error correcting file transfer data transmission protocol that sends information in 1024-byte (1k) blocks. Checksums are done
on each block and the result is sent along with the block. If the result does not check out at the receiving end, a NAK (Negative
AcKnowledgement) is sent to retransmit that block. If the block checks out, an ACK (ACKnowledgement) is sent.
XMODEM An error correcting file transfer protocol that sends informaton in 128-byte blocks. Checksums are done on each block and the
result is sent along with the block. If the result does not check out at the receiving end, a NAK (Negative AcKnowledgement) is sent
to retransmit that block. If the block checks out, an ACK (ACKnowledgement) is sent.
KERMIT A very reliable asynchronous file transfer protocol that can communicate successfully with virtually any system. Because of this
portability, throughput is significantly reduced.
ASCII Sends TEXT ONLY files directly to the computer screen. Is very slow. Binary or graphics files cannot be transferred using the ASCII
protocol.
Rules for Using File Transfer Protocols
For the best results when sending or receiving a file, follow these basic rules:
If both systems support ZMODEM, use it!
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Both the sending and receiving modem must use the same file transfer protocol. BBS or online services usually inform you which protocols
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are available.
Most communications software packages must be informed of the name of the sending (uploading) or receiving (downloading) file before file
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transfer can begin, and when a file transfer is about to take place. See your communications software manual for specific information.
CAUTION: When files are shared, the risk of getting a computer virus always exists. We recommend the use of virus scanning
software to make sure the files you receive and send do not contain viruses.
Sending a Data Transmission
All communications software allows for automatic dialing. See your software documentation for instructions.