TELSAT® COMMUNICATIONS LTD

Null Modem Connections

If you want to use serial download or to upload, you will need a null modem cable to connect your receiver to your pc. This cable can also be used for remote control programs to control your receiver. The details below show the required connections, although most computer shops sell suitable cables.

PC 25 pin	PC 9 pin	Signal type	IRD 9 pin	Signal type
7	5	GND	5	GND
2	3	TXD	2	RXD
3	2	RXD	3	TXD
5	8	CTS	7	RTS
4	7	RTS	8	CTS
6	6	DSR	4	DTR
20	4	DTR	6	DSR

9 Pin D-SUB Female 25 Pin D-SUB Female

9 PIN D-SUB FEMALE to Computer.
9 PIN D-SUB FEMALE to IRD.

	D-Sub 1	D-Sub 2
Receive Data	2	3	Transmit Data
Transmit Data	3	2	Receive Data
Data Terminal Ready	4	6+1	Data Set Ready + Carrier Detect
System Ground	5	5	System Ground
Data Set Ready + Carrier Detect	6+1	4	Data Terminal Ready
Request to Send	7	8	Clear to Send
Clear to Send	8	7	Request to Send

9 PIN D-SUB FEMALE to Computer.
25 PIN D-SUB FEMALE to IRD.

	D-Sub 9	D-Sub 25
Receive Data	2	2	Transmit Data
Transmit Data	3	3	Receive Data
Data Terminal Ready	4	6+8	Data Set Ready + Carrier Detect
System Ground	5	7	System Ground
Data Set Ready + Carrier Detect	6+1	20	Data Terminal Ready
Request to Send	7	5	Clear to Send
Clear to Send	8	4	Request to Send