Browse Prior Art Database

Automatic Port Location Identification Mechanism

IP.com Disclosure Number: IPCOM000046491D
Original Publication Date: 1983-Jul-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 3 page(s) / 41K

Publishing Venue

IBM

Related People

Annunziata, EJ: AUTHOR [+3]

Abstract

The physical location of a device on a local area network (LAN) system is determined by measuring the elapsed time between the beginning and ending of an electrical event. The measured elapsed time is used to access a table-lookup in which physical locations are correlated or paired with elapsed time.

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Automatic Port Location Identification Mechanism

The physical location of a device on a local area network (LAN) system is determined by measuring the elapsed time between the beginning and ending of an electrical event. The measured elapsed time is used to access a table-lookup in which physical locations are correlated or paired with elapsed time.

Fig. 1 illustrates a port interface and a device interface for a balanced transformer-driven data transmission system. Relay 10 connects the device interface to the communication loop (not shown). The device interface is coupled to a node (not shown). When the phantom drive control 12 activates relay 10, the node is inserted into the communication loop. Likewise, deactivation of the relay causes the node to be bypassed and also provides a communication wrap path for the device.

For automatic port identification, the relay is placed in the wrap bypass position (Fig. 1). In this position electrical signals generated at the device interface are transmitted (in the direction shown by the arrows) over the transmission line through the relay and back into the device interface. The device interface is fitted with a mechanism 14. The mechanism initiates the electrical event, measures the event, and performs the table-lookup function. Such an event may be a series of electrical pulses or the like. The pulses are transmitted over the transmission lines through the relay and back into the device interface. As signals are returned to the device interfaced, the signals are monitored or counted.

An electrical event and event complete signal means 16 reside in the port interface. After a predetermined number of signals are outputted from mechanism 14, a signal is outputted from signal means 16. This signal marks the end of the electrical event. The count which is accumulated in mechanism 14 is used to access a table-lookup.

The table-lookup identifies the physical location which corresponds to the particular count.

Fig. 2 shows one implementation of the automatic port identification device. In this implementation a pulse generator, a programmable counter, and an event complete signal generation device are positioned within the port. Likewise, a table-lookup, an event complete detector and a pulse generation and counting mechanism are placed within the device.

First, t...