Connecting Serial Devices To The Smartone - Globalstar SmartOne Series User Manual

Pull handshake low.
Wait 2 – 3 milliseconds.
Send command
Receive response.
Raise handshake high.

Connecting Serial Devices to the SMARTONE

The SMARTONE accepts a serial connection at 3 volt levels (Max), at 9600
baud. The relevant pins are TX, RX, Handshake and ground. The SMARTONE can
connect with devices that contain an asynchronous UART at 3 volt levels.
(High State: 2.7-3 Volts, Low State: 0 Volts. Please contact Globalstar
Support for more information.
CAUTION: NEVER attempt to connect the SMARTONE directly to the pins on a
computer's RS232 port. The voltages in RS232 are too high and can damage the
SMARTONE.
Any deviations from the above guidelines will violate all RMA requirements
and prevent any no-cost replacement.
See Appendix K for information on the Serial Input Cable for the SMARTONE
SmartOne Manual Rev 1.5 DOC# 9100-0268-01 p.71