True in some cases, but that 25 pin connector contains all the signals necessary for communication i.e. TX,RX,STR,DSR,RTS,CTS,CD,RI and GND of course.

You are absolutely Right Ijaz TX,RX,STR,DSR,RTS,CTS,CD,RI & Gnd are there in all 25 pin connectors. Actually I [ & Probably Raghu ] were referring to those additional signals which were found on old days computers. Here is the complete list of those RS232 COM port pinouts. Additional once are marked with *.

* 1. Protective Ground.
2. TD
3. RD
4. RTS
5. CTS
6. DSR
7. SGND [ Signal Gnd ].
8. CD
* 9. Reserved for Data Set Testing.
* 10. Reserved for Data Set Testing.
11. Unassigned.
* 12. SDCD [Secondary Carrier Detect].
* 13. SCTS [Secondary Clear To Send].
* 14. STD [Secondary Transmit Data].
* 15. DB [Transmit Clock].
* 16. SRD [Secondary Receive Data].
* 17. DD [Receive Clock].
* 18. LL [Local Loop].
* 19. SRTS [ Secondary Request To Send].
20. DTR
* 21. RL/SQ [ Signal Quality Detector / Remote LoopBack].
22. RI {Ring Indicator].
* 23. CH/CI [ Signal Rate Selector ].
* 24. DA [ Auxilary Clock ].
25. Unassined.

Regards,
Prahlad Purohit