Via X.25 host. The X.25 host can access the network at the SEN or LEN using 4-wire CDI at 16 kbps over a amximum distance of 4 km. A host can access the network using RG-58 thin coaxial cable. The maximum total length of the LAN RG-58 cable is 185 meters. One LAN can have 29 hosts.
Computers can access the network through concentrators.
The concentrators connect to TPN using one of the X.25 ports on the packet switch or connects to the packet switch using an 802.3 connector. The concentrater accepts mail from users. It delivers local mail and routes the rest to distant concentrators. If that is unsuccessful then it routes mail over a circuit switch. If that doesn't work the concentrator gives an error message to the sender.