ftpmail@decwrl.dec.com ftpmail@cs.uow.edu.au
In the TEXT of your message, put the word "HELP". FTPMAIL lets you uuencode binary files for transfers. It can split large files up into several messages, thus helping you around local restrictions on the size of each incoming mail message.
Chapter 13: Cheaper and better communication ============================================
Packet data services and data transportation services like Tymnet Outdial, Infonet, Internet, and PC Pursuit may help keep costs down. About reducing the cost of using mailing lists.
Many users access online services by calling them directly. A lot pay extra for long distance calls to other cities and countries, even when this means inferior transmission quality (like when noise characters degrade the data). Others investigate other routings for their data. One option is the packet data networks. Most countries have Public Data Networks (PDNs) operated by local telecommunications authorities. These services are often cheaper than direct calls for some applications, but more expensive for others. Before using a packet data network, you'll need to establish a "Network User Identification" (NUI) with the PDN carrier. You must also know the Network User Address (NUA) of the hosts that you want to access. In Scandinavia, the local PDNs are called Datapak. They can be accessed by direct local calls or through leased lines. To personal users, direct calls are least expensive. A leased line may be cost efficient when the daily volume is high, like in a company. When you communicate with online services through a PDN, the latter will split your data and bundle it in standard envelopes or 'packets'. Each packet is marked with a code and sent out into the data stream. Based on this code, the packet is routed from computer center to computer center until it reaches its final destination. There, the information will be reassembled into its original form before being handed over to a user or online service. It is almost like traveling by train. The price per packet or traveler is lower than what it costs to rent the whole train for your trip. National telecommunications monopolies were the first to offer packet data services. Their rates were moderately lower than for long distance calls, but it was hard to find the relationship between real costs and prices. This is still the situation in many countries. Throughout the world, efforts to privatize nationwide phone networks continue. In many countries, this has given us some interesting competitors offering attractive rates for similar services. Their rates differ considerably from country to country, as does the quality of transmissions. The advantage of using packet data also varies considerably, by application and by country. The best routing for retrieval of online news may be impossibly expensive for chats or complex online jobs. We can offer no hard rules of thumb, except this:
Compare rates regularly!
What is cheapest? ————————- Some networks charge by the hour, while others charge by volume (number of characters transferred per minute). When volume is low, your best bet is to use network services with a low price per minute and high prices for volume. When volume is high, you may be better off using those charging by the minute. To estimate costs reliably, you'll need statistics. Since your usage probably differs from what others do, start accumulating experience data now. Like this:
On services only charging for connect time
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Capture trip information to a log file. Register the following
information:
* number of minutes connected
* modem speed
* number of characters transmitted.
Some communication programs can do this automatically for you.
On services charging for time and volume
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Log the following information:
* number of minutes connected
* modem speed
* number of segments or packets (measurements of volume)
You need this to estimate the average volume of data transferred by minute. Here are some general experiences and hints: Long streams of data without stops are cheaper through services that only charge by the minute. Retrieving software is a typical high volume application. Trips that include navigation from conference to conference, with a little bit of up- and downloading here and there, make the average transfer speed fall dramatically. It's like driving through a big city at 150 kilometers per hour. Red lights will reduce the average speed considerably. The actual transferred volume of text per minute will differ from place to place (geographically), and often also from call to call. It depends on factors like: