First Alert T-1000 Data Transfer Sequence, Interface timing

Technical Specifications

The column heading “Direction” refers to the direction of signal flow as viewed from the printer.

“Return” denotes the twisted-pair return, to be connected at signal ground level. For the interface wiring, be sure to use a twisted-pair cable for each signal and to complete the connection on the return side. To prevent noise, these cables should be shielded and connected to the chassis of the host computer or the printer but not at both ends.

All interface conditions are based on TTL level. Both the rise and the fall times of each signal must be less than 0.2 microseconds.

Data transfer must be carried out by observing the ACKNLG or BUSY signal. (Data transfer to this printer can be carried out only after receipt of the ACKNLG signal or when the level of the BUSY signal is LOW.)

Data Transfer SequenceInterface timing

The illustration below shows the timing for the parallel interface.

Technical Specifications 6-7