RS232/Serial communication: Do I need DSR/DTR and CTS/RTS?

[sofakng]

I'm trying to build a console rollover cable to bluetooth adapter. (The ports on the back of networking equipment (routers, switches, etc) often have an RJ45 port to connect a rollover cable and then a PC for configuration. The rollover cable is basically RS232 over an 8P networking cable.)

The pins on the RJ45 connector include all of the RS232 data lines:

• CTS
• DSR
• RxD
• GND
• TxD
• DTR
• RTS

I know I need to use an RS232 to TTL converter, but none of the Teensys support DSR/DTR (and only 3.0+ support CTS/RTS).

I'm not that familiar with RS232 (and serial in general) so do I really need those pins? Would it depend on the router/switch I'm connecting to? Also, the Bluetooth adapter (RN-42) doesn't support DSR or DTR so I'm not sure if I need to connect those somehow as well?

Thanks for any advice!

 

[Epyon]

In all my years working with serial comms, I have never seen a use for DSR. Afaik it's something archaic from the modem days of old. DTR is also seldom used.

I've used managed switches from Dell, Netgear and D-Link with RS232 and iirc just having TX, RX and GND did the trick.

 

[PaulStoffregen]

so do I really need those pins?

It really depends on what your console equipment does with those pins, if anything. There's a chance it might "just work" if you do nothing with those signals, or if you short DSR & DTR together.

 

[sofakng]

OK - I'll give it a try. Thanks everybody