External Link Setup - Redpost RPC-80 Manual

EXTERNAL LINK SETUP

This section covers the serial format settings and use of the External Link.
The External Link menu allows you to set the serial format for communications on
the link.
A series of menus lets you choose the:-
Baud Rate ( 300 to 19200 )
Number of Data Bits ( 7 or 8 )
Number of Stop Bits ( 1 or 2 )
Parity ( None, Odd or Even )
Handshake (Hard or Soft)
All these must be set up to match the serial format of the external computer
connected to the external link.
The final menu in this series lets you select the type of serial handshaking as either
H H RTS/CTS or S
ARD ANDSHAKE
explained in more detail below under the sub-heading "Serial Handshaking". The
handshaking must be chosen to match that of the external computer connected to
the external link.
External Link socket
The External Link socket is a female 25 way "D" connector arranged in the RS232
Data Terminal Equipment (DTE) format. The connections are:-
Pin Signal Name
1 Chassis ground
2 Transmit Data (TXD)
3 Receive Data (RXD)
4 Request to Send (RTS)
5 Clear to Send (CTS)
7 Signal ground
14 (test signal)
20 Terminal Ready (DTR)
Serial handshaking
When serial communications take place between two parties there may be times
when either party is temporarily unable to receive data. In order to prevent data from
being lost the communication is controlled by a handshake system that signals to
each party when the other party is ready and able to receive.
Hard Handshake
In the Hard Handshake system the handshaking is managed by two extra signal
connections. The signals are described below from the point of view of the RPC-80.
Clear to Send (CTS) is an input to the RPC-80 that controls the transmitter in the
RPC-80. The signal comes from the RTS or DTR output of the external computer.
When CTS is On the RPC-80 will transmit its data, when CTS is Off the RPC-80 will
wait and not transmit.
H XO
OFT ANDSHAKE
in/out notes
out
in
out hard handshake
in hard handshake
out fixed "Off" (-9 volts)
out fixed "On" (+9 volts)
/XO . These terms are
N FF
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