Do companies need to have a high-speed Internet connection, such as ADSL, to download bidding documents and/or for the electronic transmission of their submissions?

No, it is not necessary to have a high-speed Internet connection such as ADSL to download bidding documents and/or transmit submissions electronically (candidatures and bids). However it is undeniable that such a high-speed link is in practice very useful because it allows much faster Internet exchanges.