Uniden UBC800XLT Owner's Manual download pdf (Page 24)

channels (typically 10, 20, or 28 total channels). When a user presses Push To

Talk (PTT) to transmit, their radio first sends the person’s talk group information to

the control channel. The computer then assigns that talk group to a specific voice

channel and transmits that data over the control channel. All radios in that talk

group switch over to the assigned voice channel and the user can begin speaking.

This all typically takes place in about a second. The person transmitting hears a

beep from their radio when the channel is assigned. Then it is OK to start talking.

The systems in use are:

Motorola Type I — the radios send the radio ID, the fleet and subfleet talk group

ID to the control channel each time they transmit. To program a Type I system, you

need to know the system’s fleet map. The most common fleet maps are included in

the Reference section in this manual. You can also find fleet map resources on the

web such as at http://www.radioreference.com.

Motorola Type II — the radios only send the radio ID and radio channel code to

the control channel. The central computer keeps a database of radio ID’s and

which talk group is assigned to which channel code for each radio, so with this

system the user’s radio sends only about

/3 the data as a Type I system with each

transmission. Type II systems do not use Fleet-subfleet talk groups; instead they

use a 5-digit ID for each talk group.

Type IIi Hybrid — these systems support a mix of both Type I and Type II users.

Like Type I systems, you must know the system’s fleet map to ensure proper

tracking.

EDACS Trunking

EDACS trunking works in much the same way as Motorola trunking with a couple

of major differences. In an EDACS system, each frequency used by the system is

assigned a Logical Channel Number (LCN) so that less data needs to be

transmitted by the control channel. Talk groups are assigned in an

Agency-Fleet-Subfleet (AFS) hierarchy.There is one variation of EDACS called

SCAT that your UBC800XLT can monitor.

Logical Channel Numbers — each frequency used by the system is assigned an

LCN. This information is programmed into each user radio. When a user presses

PTT, their radio sends their AFS information to the control channel. The computer

then assigns that talk group to a channel and sends the LCN so that all other

radios in that talk group will switch to the correct channel. To program an EDACS

system in your scanner, you will need to know both the frequencies used by the

system and the LCN for each frequency.

UB356ZH.fm Page 24 Wednesday, December 19, 2007 11:28 AM

1 2 ... 19 20 21 22 23 24 25 26 27 28 29 ... 143 144

No comments

Uniden UBC800XLT Owner's Manual Page 24