Why is a T1 connection slower than my home cable connection?

If you are referring to T-1 being 1.5Mbps aand cable or ADSL being 2.5Mbps+ you are confusing speed with bandwidth. T-1 lines are dedicated bandwidth meaning you will receive your allocated bandwidth no matter what the traffic is. With Cable and ADSL you will be sharing the bandwidth with others in your neighborhood (See you TOS agreement). you may have 6 Mbps at 2 am and at peak times, 2 pm, you may only get 150 Kbps. I have had a cable modem since '97 (6Mbs\768Kbps) and I have seldom scene over 2 Mbps and it i never sustained. It usally falls off to 200 to 500 Kbps. That is because the sites you connect to pay for high bandwidth so they choke down that bandwidth you can access their site with. If you notice Download.com tops between 150 Kbps and 250 Kbps (Sometimes a little faster). If they didn't they could not afford the fees.

What you are promised and what you get are different things.

Each channel of a T1 is 56kbps - unless it's clear channel, the you get 64kbps/channel. The full band-width if all channels are used = 1.544 kbps...allowing for overhead & payload.

I'd be really surprised if you're exceding that rate on any "high speed" connection. Whether is't cable, dsl, or other.

It is probably overloaded.