User Manual Part 1

CHAPTER 5
RS-232C/422/485 INTERFACING
Revised: 8 Oct 03 5-2 EST P/N AA104
FLOW CONTROL
The ESTeem can be enabled to support SOFTWARE or HARDWARE flow control.
Software Flow Control
Software flow control is enabled by the XSFLOW (on/off) command in the ESTeem. When XSFLOW is ON the ESTeem will
respond to <XOFF>, (stop) and <XON>, (off) commands from the RS-232 port. The factory default setting is OFF. The default
value for START is 17 (CTRL Q) and for STOP is 19 (CTRL S).
Hardware Flow Control
Hardware flow control is enabled by the XHFLOW (on/off) command in the ESTeem. The factory default value is OFF.
When XHFLOW is enabled (on) the control signal lines, Request To Send (RTS, pin 4), Data Carrier Detect (DCD, pin 8), and
Clear To Send (CTS, pin 5) are available to the user at the RS-232C connector. The CTS and RTS signals are used to control the
flow of data into and out of the ESTeem.
The CTS signal on pin 5 is used to control the data into the ESTeem. When CTS is set (high on pin 5) the modem is ready to
receive data. When CTS is reset (low on pin 5) the ESTeem is not ready to receive data.
The RTS signal is used to control data out of the ESTeem. RTS is set (high on pin 4), by the user to indicate to the ESTeem that
the user is ready to receive data. When reset, the user is not ready to receive data. (NOTE: Low = On, High = Off).