Function_List_Signalling.md

VBA Serial Port Functions

check input and set output COM Port signals

Input signals

First parameter (1) is a valid¹ COM Port number on host PC

VBA Function	Signal	Description	DB9 Pin	DB25 Pin
device_ready(1)	DSR	Data Set Ready	6	6
device_calling(1)	RI	Ring Indicate	9	22
carrier_detect(1)	CD	Carrier Detect (RLSD) 2	1	8
clear_to_send(1)	CTS	Clear To Send	8	5

• Functions return True if port valid, started, input signal active and Windows GetCommModemStatus returned True

Output signals²

First parameter (1) is a valid¹ COM Port number on host PC

VBA Function	Signal	Action	Description	DB9 Pin	DB25 Pin
request_to_send(1,0)	RTS	Clear	Request To Send	7	4
request_to_send(1,1)	RTS	Send	Request To Send	7	4
signal_com_port(1,1)	XOFF	Set	Flow Control Off	3	3
signal_com_port(1,2)	XON	Set	Flow Control On	3	3
signal_com_port(1,3)	RTS	Send	Request To Send	7	4
signal_com_port(1,4)	RTS	Clear	Request To Send	7	4
signal_com_port(1,5)	DTR	Send	Data Terminal Ready	4	20
signal_com_port(1,6)	DTR	Clear	Data Terminal Ready	4	20
signal_com_port(1,8)	BREAK	Send	Line Break Condition	3	3
signal_com_port(1,9)	BREAK	Clear	Line Break Condition	3	3

• Functions return True if port valid, started and Windows EscapeCommFunction returned True

Footnotes

1. Valid Minimum and Maximum port numbers should be defined in declarations section at the start of the module. ↩ ↩²

2. Receive Line Signal Detect ↩ ↩²

3. see - Escape Comm Function signal values ↩ ↩² ↩³ ↩⁴