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Data Terminal Equipment (Dte) Attachment in a Fan-In/Fan-Out Modem

IP.com Disclosure Number: IPCOM000039679D
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Epenoy, G: AUTHOR [+2]

Abstract

In a Fan-in/Fan-out modem, several DTEs are attached to a single modem according to normalized interface V 24 by means of control modules. The signals corresponding to each DTE are loaded in a register which is read (or written) by the microprocessor of the modem, each DTE being assigned a different address. However, before initiating the transfer of data, the microprocessor has to read a register wherein are stored the "Request to Send" (RTS) signals of the DTEs. Due to technological limitations, only two junctions V 24 can be managed by a single control module. Assuming that 4 DTEs (A, B, C and D) are attached to the modem, two modules are necessary to control the 4 corresponding junctions. The utilization of two identical modules is made possible by the implementation shown in the figure.

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Data Terminal Equipment (Dte) Attachment in a Fan-In/Fan-Out Modem

In a Fan-in/Fan-out modem, several DTEs are attached to a single modem according to normalized interface V 24 by means of control modules. The signals corresponding to each DTE are loaded in a register which is read (or written) by the microprocessor of the modem, each DTE being assigned a different address. However, before initiating the transfer of data, the microprocessor has to read a register wherein are stored the "Request to Send" (RTS) signals of the DTEs. Due to technological limitations, only two junctions V 24 can be managed by a single control module. Assuming that 4 DTEs (A, B, C and D) are attached to the modem, two modules are necessary to control the 4 corresponding junctions. The utilization of two identical modules is made possible by the implementation shown in the figure. The inputs I, J, K, L are decoded by either module in order to provide for three outputs: I J K- L- corresponding to junction A or C, I- J- K L corresponding to junction B or D, and I- J- K L corresponding to the RTS register. The connections shown in the figure are such that only one junction is selected when one of four different addresses is applied to the 4-wire input of the module, and the RTS register is selected for each module with a fifth different address. Such an arrangement could be extended to the connection of N DTEs, by means of N/2 identical modules.

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