Node-attached asynchronous ports

The 128-port adapter, available for the Micro Channel, ISA, or PCI bus, allows attachments of one to eight remote asynchronous nodes (RANs).

Each RAN has 16 asynchronous ports for connection to devices and are separately powered units. Up to four RANs can be daisy-chain-connected from each of two connections on the 128-port adapter card. RANs can support 16 EIA 232 devices or 16 EIA 422 devices. The 128-port controller is an intelligent adapter that increases the number of asynchronous sessions possible at a given CPU usage level.

The following are additional characteristics of the 128-port feature:

• RANs may be located up to 300 meters from the system processor using 8-wire shielded cabling while maintaining full performance ratings.
• Distance may be extended to 1200 meters by reducing the data rate between the RANs and the system processor.
• RANs may be remotely located from the system processor using a synchronous EIA 232 and EIA 422 modems. Each four-RAN daisy chain is allowed only one modem pair at some point in the chain.
• System performance is enhanced by offloading tty character processing from the system processor.