COLLISION AVOIDANCE IN A HALF-DUPLEX COMMUNICATION SYSTEM

摘要

In a half-duplex communication system in which additional delays in the communication channel may cause a message collision between a message and a response, a timer based collision prevention circuit (40) is utilized to prevent the message collision. The collision prevention circuit (40) determines if the message transmitted by a communication device will be repeated. If the message is to be repeated, the collision prevention circuit (40) sets a countdown collision timer (44) to a predetermined period of time shorter than the shortest repetition interval of the repeated message. A response is only sent to the communication device if the collision timer (44) has not expired. If the timer (44) expires, the collision prevention circuit (40) waits for the message to be retransmitted by the source device before sending the response to the communication device.