Meinberg TCR511PEX - Manual (Page 11)

11
The 9 pin D-Sub-connector is wired to the board’s serial port. Pin assignment can be
seen from the figure above. This port can not be used as serial port for the computer.
Instead, the clock uses the port to send out Meinberg's standard time string in order to
control an external display or some other external device. The string is sent out once per
second, once per minute or if requested by an incoming ASCII ‘?’. It is also possible to
change the board’s board time by sending such a string towards the clock. Transmission
speed, framing and mode of operation can be modified using the monitor software. The
string format is described in the section ‘Technical Specifications’ at the end of this
manual.
Pin assignments of the D-Sub-connector
Only the signals of the serial interface are connected to the D-Sub-plug directly. If
another signal shall be connected to a pin of the plug, a DIP-switch must be set to the
‘ON’ position.
Whenever an additional signal is connected to the rear panel, special
care must be taken to the configuration of the cable used with the
connector. If pins with TTL level and RS-232 levels are connected to
each other, the circuits on the board may be damaged.
Only one of the switches 5 or 4 may be put in the ‘ON’ position to
connect the pulse per second with TTL level or with RS-232 level to pin 8 of the plug.
The table below shows the pin assignments for the connector and the DIP-switch
assigned to each of the signals:
Pin Signal SWITCH
1 + 5V 3
2 RxD in (RS-232) -
3 TxD out (RS-232) -
4 PPM out (TTL) 6
5 GND -
6 + PWM in 1
7 - PWM in 2
8 PPS out (TTL/RS232) 5/4
9 (reserved) 8
Those signals which do not have DIP-switch assigned are always available at the
connector. All DIP-switches not assigned are reserved and should remain in the ‘OFF’
position.