Setup & Installation 2
Protocol Handshake Types:
Two protocol handshake types are available, 2 pass and 4 pass.
2 Pass: | The host transmits an instruction to a BASIC I/O. |
| If the instruction is correctly received (i.e. valid address, instruction type |
| and correct checksum) the BASIC I/O executes the instruction and |
| returns the letter “A” and a cr or, where data is to be returned, the letter |
| “A”, then the data, followed by a two character checksum ending with a |
| cr. |
4 Pass: | The host transmits an instruction to a BASIC I/O. |
| If the instruction is correctly received (i.e. valid address, but not |
| necessarily the correct instruction type nor checksum), the BASIC I/O |
| returns an “A” followed by the Echo of the instruction and does not |
| execute it. |
| If the host then transmits an E, the instruction is executed in the same |
| manner as the 2 pass. If the Hos transmits any other character to any unit |
| on the network, the instruction is disregarded. |
The sequential display indicates the letter P followed by 2 or 4. BASIC I/Os are shipped in 2 pass mode; the sequential display indicates P2. The actual setting of the handshake protocol type is detailed following network type switch.