7.1.d – Serial Port Pin Outs
The pin assignments for the Keyspan USB 4 Port serial Adapter’s male DB9 port are illustrated below:
Pin | Name | Signal Designation |
1 | DCD | Data Carrier Detect (Input) |
2 | RX | Received Data (Input) |
3 | TX | Transmitted Data (Output) |
4 | DTR | Data Terminal Ready (Output) |
5 | GND | Ground |
6 | DSR | Data Set Ready (Input) |
7 | RTS | Request To Send (Output) |
8 | CTS | Clear To Send (Input) |
9 | RI | Ring Indicator (Input) |
In order to ensure compliance with emission specifications, cables, should be shielded using braided shields and metal hoods with complete 100% contact between the shields and hoods.
External Loopback Connector Information
The Keyspan Serial Assistant allows you to perform two types of loopback tests – internal and external. The external test requires the use of a special loopback connector. This connector requires a “DB9 Female Loopback plug” with the following wiring:
Pin(s) | Wired to | Pin(s) |
1 | 4, 8 | |
2 | 3 | |
6 | 7, 9 |
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