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

Additional output frequencies Connectors: These connectors provide additional out­put frequencies which are, from left to right, 100kHz, 1MHz, 5MHz and 10MHz.

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.

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