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Browse Prior Art Database

Transmitter Receiver Terminal Service Check

IP.com Disclosure Number: IPCOM000074539D
Original Publication Date: 1971-May-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Holloway, JT: AUTHOR [+3]

Abstract

A transmitter/receiver is checked for service problems by isolating the terminal from the communication line and utilizing internal data paths to check both receive and transmit functions.

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Transmitter Receiver Terminal Service Check

A transmitter/receiver is checked for service problems by isolating the terminal from the communication line and utilizing internal data paths to check both receive and transmit functions.

When transmitting, characters entered at keyboard 11 are transferred in parallel to P register 13 to effect print out on printer 15. The character in P register 13 is transferred to T register 15 and then to serializer register 17. The character in serializer register 17 is gated out serially to line adapter unit 19 and thence to the communication line 21. Characters received at line adapter 19 are transferred serially to the serializer register 17 and thence to the T register and P register to printer 15. In order to isolate terminal errors from line adapter errors, a local mode is provided which causes data entered from keyboard 11 to be circulated to the serializer register 17 and then to be returned over the same data path to effect a print operation on printer 15. Thus, in local mode, the same character will be printed twice indicating a successful test. Both start of transmission codes and end of transmission codes can be locally circulated to insure proper system response and function. A further test is performed by gating a bit from a one-bit generator 23 through OR gate 25 to the serializer register 17 and causing that bit to shift a predetermined number of cycles through the serializer. Additional bits may be loaded under co...