depending on the size of your funds, you might consider going leveraged trading (proprietary) with all the newer software features that these firms offer.
for example..
Echotrade uses/used Sterling Technologies Sterling Trader Pro. It performs wonderfully over dialup.
Webroot optimizes your machine configuration for hyper transmission over your broadband.
Other software platforms (eSignal, Etrade, AmiBroker, Ameritrade, etc...) are optimized so as to use a narrow bandwidth for data, hence fully capable over dial-up modem.
this is a worth alternative, however, fully question their tech's before committing to thier platforms and posting your monies with them...