Did the ECI have 64 ports per line card available when BT first rolled them out?
ECI 128/256 is how BT designate them when applying for planning permission. I think the 128/256 may actually have something to do with power consumption - ie how much they pay for electricity.
afaik Openreach have only deployed M41's.
It would appear once they realised the M41's may have a problem with vectoring, they switched back to Huawei.
afaik all of them have 64 ports per line card. They are using VTU-C64 line cards in the M41s which as ejs said, can take up to 4 line card. Therefore if when applying for planning they assume the M41 will have 2 line cards then it will be designated ECI 128, or ECI 256 for 4 line cards.
In actual fact its not quite so straight forward as it being an indicator of the number of line cards.. but more the number of IDC Blocks.
If you look on the
FTTC cab page it shows a couple of photographs of one cab provisioned as ECI 256 and another which is designated as an ECI 128.
This particular cabinet is designated ECI 256 - note provision availability for 4 line cards and full IDC rack
...
This cab would be designated EC1 128 - note provision for 2 line cards and only 128 IDC connectors
Note how the cab which according to planning permission was described as an ECI 256. Upon installation it only had one line card.. but had 256 IDC connectors - its a relatively easy task to slot in more line cards when needed.