The consensus seems to be that data transfer rates of 38,400bps are
mythology, with 9600bps being more realistic, and even that is only
the connect protocol, not the actual data transfer rate.
Dr. Neuvians performed a test in Zimbabwe, transfering 200kb in 5.5
minutes, which translates to about 4800bps -- Dr. Lisse might check
my numbers on his calculator, thanks.
Thanks to Dr. Neuvians, here's an updated cost analysis on using
GSM for email.
US$30 per month ISP subscription
US$12 per month cell phone subscription
US$0.12 per minute cell time
Variable charge estimate:
5.5 minutes for 200kb or 4800bps
(Note: does not include handshake which has little
impact on large file transfers)
Translates to 27.5 minutes for 1MB
Assume 25 MB per month volume
Translates to 687.5 minutes online per month
US$82.50 per month online time
So this user in Zimbabwe could expect to pay
US$124.50 per month for email only. If they had five
workstations, each doing about the same volume, then
their costs would be about $622.50 per month, perhaps
high enough for them to justify a much higher quality
and slightly higher cost dedicated wireless link.
That's most helpful, and I'll communicate it to my colleagues in
Jeff @ Washington
Dieter Neuvians writes:
> I'am using e-mail via GSM within Zimbabwe when I don't have access to a
> telephone line.
> ISP is UUNet Africa (Internet Unlimited Zimbabwe) charging Z$ 13,200 per
> year for unlimited internet access (e-mail only is cheaper). GSM
> provider is NetOne (PTC Zimbabwe) charging Z$ 450 monthly fee and about
> Z$ 4.50 per minute (depending on time of the day / 1 US$ = 38 Zimbabwe
> Connection is with 9,600 bps, handshaking takes about 20 seconds, 100 kB
> mail (one message) uploading 3 minutes, 10 seconds, downloading 2
> minutes 20 seconds.
> Cellphone: Ericsson SH 888 with in built modem.
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