Cavebear Catalog - Techno - RealMan's LAN Initial Specification
Date: 4 Jun 92 18:36:09 GMT
From: firstname.lastname@example.org (Steven D Ourada)
RealMan's LAN Initial Specification V 0.1
I) Physical Specifications
The physical transmission medium shall be a pair of standard 20 gauge copper wires, wrapped in Black Electrical Tape. Each node shall be connected to the common Aeather by means of cutting the copper wire pair, twisting the new node's wires together with the two exposed ends of the Aeather, capping the splice with Those Orange Thingies, and wrapping the entire splice in Black Electrical Tape.
Rationale: Who needs sissy coax? "It protects the network from
It prevents _leeaakage_. Oh my, whatever will we do about _noise_ and _leeaakage_?"
II) Electrical Specifications
Transmissions shall occur by means of holding the Signal wire at a specified level of voltage above the Ground wire for a specified time for each bit.
Voltage level is determined by the following formulae:
'1' voltage level=Ambient voltage level * 3.
'0' voltage level=Ambient voltage level * 2.
Bit duration is determined by the following formula:
Bit duration=Bit duration from last failed transmission + 2 ms.
Receptions shall occur by means of measuring the voltage difference between the Signal wire and the Ground wire. The signal with the highest potential and the longest duration shall be received; all others shall be ignored.
Note: The above transmission procedure guarantees that collisions are handled properly. Also note that the transmission specifications dictate that no Surge Protectors can be used on the Aeather, since valid voltages may reach arbitrarily high levels. Prototypes of this network with three nodes transmitting at speeds near 1000 bps have reached voltages of 38 kV; networks with more nodes or higher speeds may exceed this.
III) Communication Protocol
Transmissions may occur at any time. Data Packets may be of any length, and must be preceded by an Address Packet consisting of a node name or a HEYYOU (0x3c3c3c3c) Universal Address Packet.
Receivers shall only listen to Data Packets addressed to them, unless the contents the Data Packet seem Interesting. If a Garbled Packet is received, the node may transmit either an WUT? (0x2a3483bf) Retransmit Signal, or a BLLSHT (0x31415926) Transmitter Denial Signal.