A bit of background first: the distinction between incoming and outgoing RFCOMM (Bluetooth stack protocol for virtual COMs) ports is necessary because it's always one of the communicating devices that initiates the connection (a bit similar to TCP sockets - where you have server and client).
- The outgoing COM port is used when the PC initiates the connection to the
remote device (opening the port initiates RFCOMM connection to the remote device).
- The incoming COM port is used when the remote device initiates the
connection.
Once the connection is opened it is bidirectional, regardless of the type.
That said, this Bluetooth module supports both master and slave mode (see manual chapter 2), that's why it advertises 2 RFCOMM/SPP ports, I guess. If you want PC to initiate the connection, use COM6, otherwise use COM7.
Why you see no echo in PuTTY? By default there's no local echo, and you actually shouldn't see any characters you type (unless you short UART_RX to UART_TX, or have some real device attached there to communicate with). The module itself is transparent (in the data mode, that is).
Also, baud rate etc. shouldn't really matter for Blueooth connection - note, that chapter 3.2 refers to configuring the device via physical serial port (UART_RX/TX pins, i.e. from the device side), while 3.3 describes configuring over virtual port (i.e. from the PC side). I somehow feel you're confusing the module sides ;)
This excerpt from the manual is quite important:
To connect to FireFly, browse for
services, you should see: “SPP”
profile with a virtual COM port. Open
this virtual COM port to create a
Bluetooth connection. Once connected,
the device will be in data mode
allowing data to flow in both
directions as if the serial port were
locally attached to the PC. The device
must be in command mode for
configuration and programming. To
enter command mode type “$$$” (three
dollar signs) from either the remote
Bluetooth connection or the local
serial port connection. You must enter
command mode within 60 seconds
(configurable by setting the config
timer).
Cool module, btw!
Two parameter of antenna which are important are
- Frequency range
- Impedance
Frequency range of antenna which is shown with antenna's frequency present center frequency of antenna and it's bandwidth and Impedance which is used for preventing losses of traveling wave travels through the device and antenna. Your Bluetooth modules run in 2 GHz band and GPRS is used in 900 MHz and sometimes 1800 MHz. GPRS antenna is modified for these frequency and it will has low gain in 2 GHz. Also it is hard to match impedance for 2 GHz. So, it is not suitable to use for Bluetooth. But i recommend see antenna specification and your Bluetooth band. If your antenna has gain in Bluetooth band with considering impedance it could be used.
Best Answer
If I understand you are trying to send an AT command over the RF link - this is not how it works.
You need a wired connection to the TX/RX pins on the module, and send the AT commands this way (this is how you can send AT commands before pairing)
Here is an example schematic:
Here is a run through of connecting a HC06 to an Arduino nano.
EDIT- if you are not planning to connect using a microcontroller, then you will need a USB to RS232 cable (TTL level). You can get them with the connectors to fit the header on the modules like this one: