You can purchase a standard serial communication cable from local computer stores. 

However, these cables are usually of 6-12 ft in length. This may not be sufficient in length for your application 

and may have to make one from scratch. Even if you bought a ready made standard RS232 cable, 

the cable still must be configure as shown below.

 What you will need

25-Position Male Solder D-Sub Connector

25-Position D-Sub Metal Hoods for 25-Pin D-Sub Connectors

9-Position Female Solder D-Sub Connector

9-Position D-Sub Metal Hoods for 9-Pin D-Sub Connectors

Category-5 PC-Network Wire

Note** Newer laptops do not have serial communication port and you will need to purchase USB to Serial Port converter.

USB to Serial Port Converter