US 6614545

Patent Overview — US 6,614,545 B1

Title: Communication scheme for imaging systems including printers with intelligent options

Patent number: US 6,614,545 B1
Application number: US 08/853,767
Inventors: David Brian Langer; Steven Wayne Parish; Edward Carlton Sharp
Original assignee / current assignee (as listed): Lexmark International, Inc.
Priority/filing date: 1997-05-09
Publication (grant) date: 2003-09-02
Legal status (as listed): Expired – Lifetime; adjusted expiration 2020-01-24

Purpose. The patent addresses communication between a printer controller and "intelligent" optional support devices (e.g., paper handling options such as input sources, output destinations, duplexing, stacking, and collating). Each intelligent option typically has its own microprocessor and microcode and is managed as a "black box." The excerpt identifies problems with prior arrangements: low-bandwidth serial links, the need to address every device individually to send a common command such as "reset," and error-reporting schemes that either reserve a response byte value (e.g., 255) or require timeout-and-retry, which cannot distinguish an ailing communications link from a device malfunction.

Plain-language scope. The system comprises a printer with a printer controller, a first optional support device with a first device controller, and a bidirectional serial communications path including a first trunkline having a unique trunkline address. The first device controller initially responds to that unique trunkline address; the printer controller automatically assigns a unique device address, commanding the first device controller to respond to a first device address. Logic circuitry continues the first trunkline through the first optional support device to the next device when enabled. The printer controller sequentially and automatically commands optional support devices to respond to unique device addresses. Plural trunklines may extend from a common electrical connection to a communication bus, each with a unique trunkline address, with each device originally programmed to respond to one such address.

Source: https://patents.google.com/patent/US6614545/en

What the excerpt does not establish. It is an excerpt only; the full specification, all claims, the drawings (FIG. 1 and FIG. 2 are referenced but only partially described), and the complete prosecution history are not reproduced. The excerpt does not establish the exact claim language or claim count, the specific error-reporting mechanism ultimately claimed, or the detailed operation of the automatic addressing sequence. Dates and legal status are as listed by the source and are assumptions, not legal conclusions.