The Longacre PC Download option is available on all Longacre Computerscales DX models. It may be added to any variant of the DX by special order. The hardware in the scale control box appears to be identical for both the PC Download option and the Printer option.
A small connector is present on the left hand side of the control box, and a cord is provided which presents a 9 pin female serial connector with 2 pins (pins 2 & 5) connected. According to Longacre, this cord is different from the cord supplied with the printer option. The 9 pin connector is slightly fragile; use care with it. If the black plastic shell comes loose, do not pull it out of the male connector by the wires.
The serial port configuration is 9600 baud, 8 bits, one stop bit, no parity.
Weights are transmitted as ASCII strings, terminated by <cr><lf>. Each string consists of 4 values separated by commas. From left to right, the values are the weights for the RR, RF, LR, and LF pads. If a pad is not connected, its weight will be transmitted as four hyphens. Otherwise, the weight will be transmitted as an unsigned decimal value in pounds if a weight is positive, or a signed decimal in pounds if the weight is negative.
The "Download to PC" button does not trigger transmission of cross weights or any other computed values.
185,----,55,---- represents 185 pounds on the RR pad, 55 pounds on the LR pad, and no pads connected for RF and LF. 145,----,----,22 represents 145 pounds on the RR pad, 22 pounds on the LF pad, and no pads connected for RF and LR.