# Serial Port

In addition to connecting to the standard serial ports on the PC, the serial port emulation in BeebEm has options to connect via TCP/IP to a local or remote IP address. You can use ROMs such as CommSoft or CommStar to connect to a Viewdata BBS, MUD server or any other type of server. Also supported is the Microvitec Touch Screen, a device that connects to the BBC Micro's RS423 serial port.

The serial IP features are selected via the RS423 dialog box, accessed from the Select RS423 Destination menu option.

## Serial Port

When the Serial Port option is selected, BeebEm will use one of the host PC's serial ports. Enter the port name, e.g., COM1 into the Port field.

## Microvitec Touchtech 501

When the Microvitec Touch Screen option is selected, together with the Options → Analogue Mousestick option, mouse input in the BeebEm window is translated into touch screen input. Software for the Microvitec Touchtech 501 can be downloaded from Paul Vernon's website.

## Serial over IP

When the IP option is selected, BeebEm will make a TCP connection to the specified IP Address. and Port. This could be the address of a host to connect to over the internet, or the "tcpser" package, which emulates a modem and handles the connection to a remote system.

To use tcpser, select 127.0.0.1 and 25232 as the IP Address and Port. Download a prebuilt Windows binary of tcpser.zip. The tcpser source code is available here.

Run the following command to start up an instance suitable for the localhost setting to talk to:

> `tcpser -v 25232 -p 6400 -l 4 -s 9600`

This will also allow incoming connections, as that does all the answering business and passes the caller onto the Beeb via the pre-existing connection. This handles the handshake lines if you enable IP232 mode, so dropping RTS will drop an outward connection. Similarly DCD going up will be passed through to CTS.

Add the Commstar.rom to your ROM configuration (see ROM Software) and start up BeebEm. In the RS423 dialog box, select IP, IP Address 127.0.0.1, and Port 25232. Click OK to close the dialog box then select RS432 On/Off from the Comms menu. Type *COMMSTAR to start CommStar. In Commstar:

- Press `M` to switch to mode 0
- Press `A` to turn off Auto line feed
- Press `I` and then `R` a few times to set the receive baud to 9600
- Press `C` to enter chat mode

You should now be able send commands to the modem (tcpser), try typing AT, you should get OK back. You can now "dial" into a server using the ATD command. Try connecting to the Ishar MUD server using ATDishar.com:9999.

The IP232 Raw Comms option controls special processing of character 255. When enabled, no special handling is applied. When disabled, for use with tcpser, when character 255 is received followed by either 0 or 1 indicates the modem's DTR state, which updates the CTS input on the Beeb's 6850 ACIA.

The IP232 Handshake option determines if the RTS handshake line is sent down the TCP/IP link or just generated locally from the presence of a valid connection. When enabled, a change in RTS is sent via the TCP connection as character 255 then either 0 or 1.

If on startup, or when ticking the RS423 On/Off menu option, BeebEm cannot connect to the specified server, or if it loses connection subsequently, it will report an error and disable RS423. Select the menu option again to try to reconnect.

BeebEm will emulate the correct receive baud rate. This makes for a very realistic experience when talking at 1200 baud to a Viewdata host! Transmitted data is just sent out as fast as it will go.