EFJohnson 7780 service manual General Information, Scope of Manual Equipment Description

GENERAL INFORMATION

SECTION 1 GENERAL INFORMATION

1.1 SCOPE OF MANUAL

This service manual contains operating, program- ming, alignment, and service information for the E.F. Johnson 7780 800 MHz portable transceiver.

1.2 EQUIPMENT DESCRIPTION

1.2.1 INTRODUCTION

The 7780 800 MHz portable transceiver is avail- able in limited keypad (3-key) and full keypad (15- key) models. In addition, standard and intrinsically safe versions are available (see Section 1.2.3). With all versions, up to 16 zones can be programmed, and each zone can contain up to 16 channels resulting in up to 256 total channels. The rotary switch on the top panel provides channel select, and an option switch provides zone select if applicable.

The 7780 is an 800 MHz transceiver which oper- ates on the 920 channels from 806-824 MHz (mobile transmit). The receive channels are 45 MHz above these frequencies from 851-869 MHz. All models can be programmed for both narrow and wide band opera- tion. With narrow band operation, the channel spacing is 12.5 kHz and maximum deviation 2.5 kHz; with wideband operation, the channel spacing is 25 kHz and maximum deviation is 5 kHz. On NPSPAC chan- nels, maximum deviation is 4 kHz (see Section 1.2.5).

1.2.2 OPERATING PROTOCOLS

The 7780 operates on analog channels utilizing the following operating protocols:

•Conventional (non trunked)

•SMARTNET II/SmartZone (trunked)

1.2.3 INTRINSICALLY SAFE MODELS

NOTE: Contact your sales representative to determine the availability of intrinsically safe models.

The intrinsically safe versions of the 7780 (see Section 1.3) meet Factory Mutual standards for opera- tion in certain flammable atmospheres. Basically, the same service information used to service standard

models is also used to service these models. Refer to Section 1.10 for more information on the intrinsically safe rating and additional requirements for servicing intrinsically safe models.

1.2.4 SYSTEMS, CHANNELS, AND ZONES

A zone and channel are selected to place and receive calls. The following describes the relationship between systems, channels, and zones.

Systems

A system as used with this transceiver is a collec- tion of channels (talk groups) belonging to the same repeater site. A system defines all the parameters and protocol definitions required to access a site. Up to

1 conventional system and 15 SmartNet/SmartZone systems can be programmed (16 total). Systems are used for programming purposes only and are not selectable by the user.

Channels

A channel selects a radio channel or talk group in a system as follows:

Conventional Mode - A channel selects a specific radio channel, Call Guard (CTCSS/DCS) squelch coding, and other parameters unique to that channel.

SmartNet/SmartZone Mode - A channel selects a specific talk group, announcement group, emergency group, and other parameters unique to that channel.

As previously described, a maximum of up to 256 channels can be programmed with the preceding modes. The conventional system can be programmed with up to 256 channels, and each SmartNet/Smart- Zone system can be programmed with up to 256 talk groups (channels).

Therefore it is theoretically possible to program any combination of these systems that produces up to 256 total channels. However, the maximum number may be limited by the available memory. For example, since more memory is required to program a SmartNet system than a conventional system, the total number

	November 1999
1-1	Part No. 001-7780-500