Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
199 words
A local communication system comprising a plurality of stations interconnected for the communication of messages made up of message units of a fixed maximum size, the stations including a first station which is designated master of a first serial data channel such that the first station alone may transmit messages via the first channel, and a second station having data processing means and interface means for receiving message units via a plurality of said data channels including said first channel, the interface means comprising a plurality of receive buffers associated with respective ones of the said serial data channels, each buffer having the capacity to receive a message unit transmitted via the associated data channel by a master station and holding such message unit until it has been read from the receive buffer by the data processing means, wherein the first station includes: (i) means for transmitting to the second station a locking signal which causes the second station to disable the receive buffers associated with all data channels other than the first channel; and (ii) means for transmitting an unlocking signal which causes the second station to re-enable the receive buffers associated with the said other data channels.
Claim 2
Dependent Claim
36 words
A system as claimed in Claim 1 wherein any message comprising more than one message unit transmitted by the first station to the second station commences with a locking signal and ends with an unlocking signal.
Claim 3
Dependent Claim
32 words
A system as claimed in Claim 1 or 2 wherein all message units of a message carry a locking signal except the last unit of the message, which carries an unlocking signal.
Claim 4
Independent Claim
32 words
A system as claimed in any preceding claim wherein the second station includes means for unilaterally re-enabling the other receive buffers if no unlocking signal is received within a predetermined timeout period.
Claim 5
Independent Claim
38 words
A system as claimed in any preceding claim wherein the interface means of the second station further includes means for signalling to a transmitting master station whether a given message unit has been received into a receive buffer.
Claim 6
Dependent Claim
59 words
A system as claimed in Claim 5 wherein the second station transmits to the first station a positive acknowledge signal for each message unit received into the first channel receive buffer, but transmits to the first station a negative acknowledge signal for each message unit transmitted to the second station but not received into the first channel receive buffer.
Claim 7
Independent Claim
28 words
A system as claimed in any preceding claim wherein the plural serial data channels are logical channels multiplexed into a single serial data channel for transmission between stations.
Claim 8
Dependent Claim
30 words
A system as claimed in Claim 7 wherein said single serial data channel is further multiplexed with user information signals for the communication of audio and/or video information between stations.
Claim 9
Independent Claim
26 words
An apparatus for use in a system as claimed in any preceding claim, the apparatus having the technical features of the first apparatus of the system.
Claim 10
Independent Claim
29 words
An apparatus for use in a system as claimed in any of Claims 1 to 8, the apparatus having the technical features of the second apparatus of the system.
Claim 11
Dependent Claim
19 words
A system as claimed in Claim 1, wherein the plurality of stations are interconnected by unidirectional fibre optic links.