The WCB402 cable is meant for daisy chaining RS-232 control to multiple instruments. It mates with the RS-232 Output Connector on the rear panel of
WCB402 RS-232 cable, 6-ft, DB 25-25 pin
What is the Pin Out for the Mini-DIN/RS-232 serial port on the back of the Poly G7500
File:RS-232 DE-9 Connector Pinouts.png - Wikimedia Commons
Tripp Lite 5ft USB to Serial Adapter Cable USB-A to DB9 RS-232 M/M 5' - serial adapter - USB - RS-232 - U209-000-R - USB Adapters
Delock Products 87713 Delock RS-232 Tester DB9 female > DB9 male
25-Pin RS-232 Loopback Plug (SunVTS 5.0 Test Reference Manual)
Best Practices for RS-232 Serial Control - Aveo Systems
DDS Pin
The Sabrent SBT-FTDI USB to Serial converter is the perfect solution for transferring data from a PDA or digital camera. The USB to DB9 provides a connection between an available USB port and the more traditional RS-232 serial port found on many devices. This adapter is designed for connections to cellular phones, PDAs, digital cameras, modems, or ISDN terminal adapters through your USB port. Simply plug your device into the adapter and the adapter into your PC or Mac.
Sabrent 6' USB 2.0 to Serial (9-pin) DB-9 RS-232 Adapter Cable CB-FTDI
audio adapters - USB-to-3.5mm 4-pin for RS-232 - Hardware Recommendations Stack Exchange
Solved: Struggling with setting up a RS-485 connection from a mass flow controller to NI cDAQ - NI Community
DB9 RS-232 Male to Blunt - All 9 Pins - 22 AWG Plenum - Serial Breakou - Custom Cable Connection