As part of The TELSTAR Videotex System a PSTN (dial-up) modem server was constructed using SIP telephone lines and US Robotics modems (these can be accessed on tel. 01756 664433). The user interface to this modem server was designed to be similar to PSS/PAD software in that, once connected to it using a modem, the PAD software can be used to connect to remote internet based services using TCP/IP. When connecting to TELSTAR directly on 01756 664433, the PAD software is configured to auto-connect to TELSTAR, this is hidden from the user and the PAD facilities are not available.
By connecting to the PAD software using the telephone number 01756 664434, the PAD prompt is presented, thereby allowing services other than TELSTAR to be accessed e.g.
At the current time the system is experimental and is restricted to only a few services and commands. The list of services can be displayed by using the HOSTS command, for example:
Any of the systems can be called and from this point the connection is made over the internet. Naturally, you will need to configure your terminal appropriately for the service you wish to access e.g. viewdata, ANSI, VT100 etc. The PAD will auto sense the data length and parity setting between the terminal and the PAD (e.g. 7E1, 8N1 etc). Communications between the PAD and the host will always use 8 bits for the data.
Connecting to a remote system can be done using the CALL command e.g.
PAD> CALL TELSTAR
Assuming the connection is successful, all characters entered and received will be to and from the remote system.
When at the PAD prompt, a list of available commands can be shown using the HELP command e.g.
HOSTS Returns the local directory of available hosts.
CALL <node> Connects to the specified host.
HELP Shows this file.
<Ctrl> P will disconnect the host and return to the PAD.