Pulse Output [CNT-91(R) only]: User definable to serve as output for built-in pulse gener­ator, gate indicator or alarm.

Optional Main Input Connectors (not with Option 23/90): The front panel inputs can be moved to the rear panel by means of an optional cable kit. Note that the input capacitance will be higher.

Type Plate: Indicates instrument type and serial number.

Fan: A temp. sensor controls the speed of the fan. Normal bench-top use means low speed, whereas rack-mount­ing and/or options may result in higher speed.

Protective Ground Terminal: This is where the protective ground wire is connected inside the in­strument. Never tamper with this screw!

Line Power Inlet: AC 90-265 Vrms, 45-440 Hz, no range switching needed.

Reference Output: 10 MHz derived from the internal or, if present, the external reference.

External Reference Input: Can be automatically selected if a signal is present and approved as timebase source, see Chapter 9.

External Arming Input: See page 5-7.

GPIB Connector: Address set via User Options Menu.

Ext. DC Connector: Part of Option 23/90 for CNT-90(XL). Range: 12-18 V Note the polarity.

USB Connector: Universal Serial Bus (USB) for data communication with PC.