LightSpeed Technologies CAT 860 user manual 13.RS-232SERIAL INTERFACE PROGRAMMING

5. Warranty, Safety	& Specifications
4. Troubleshooting
3. Optional	Accessories
2. Setup & Use
1. Overview

13.RS-232 SERIAL INTERFACE PROGRAMMING

The CAT 860 uses standard RS-232 protocols as a serial link to an external control module such as an intelligent wall panel, or a personal computer. When the Control Select switch in the “RS-232” position, the serial link offers remote access to operational control circuitry within the CAT 860 for the purpose of controlling the volume of the audio input and output ports. Additionally, the serial links allows remote queries of internal CAT 860 system status.

Serial Interface Protocol

CAT 860 RS-232 SETTINGS

Sync. Method:	Asynchronous
Stop Bits:	Accepts 1 or 2 stop bits
Baud Rate:	9600 baud
Parity:	None
Data Size:	8-bits
Connector:	9-Pin, Female D-Sub

RS-232 Data Signals

RS-232 LOGIC WAVEFORM (8N1)

Command and parameter characters travel serially along the RS-232 signal link between the external controller and the CAT 860. The command and parameter information is in the form of two hexadecimal values contained in the 8-data bits of each RS-232 character. The above graphic illustrates a typical RS-232 logic waveform representing a character (Data format: 1 Start bit, 8 Data bits, No Parity, 1 Stop bit). The data transmission starts with a Start bit, followed by the data bits (LSB sent first and MSB sent last), and ends with a “Stop” bit.

The voltage of Logic “1” (Mark) is between -3VDC to -15VDC, while the Logic “0” (Space) is between +3VDC to +15VDC.

13.RS-232 SERIAL INTERFACE PROGRAMMING CONT’D

Connector Signal Wiring
DTE PIN ASSIGNMENTS (DB-9)
1	DCD	Data Carrier Detect
2*	RxD	Received Data
3*	TxD	Transmitted Data
4	DTR	Data Terminal Ready
5*	GND	Ground (Signal)
6	DSR	Data Set Ready
7	RTS	Request to Send
8	CTS	Clear to Send
9	RI	Ring Indicator	* Only 3-Pin Connection

Command Structure

An external controller, in the form of an intelligent wall panel or a personal computer, can use the RS-232 serial link to remotely send commands to initiate actions or queries for the CAT 860. In response, the CAT 860 uses the RS-232 serial link to send acknowledgements or status data back to external controller.

There are two operational command sets; the Basic Command Set for audio switching and the Advanced Command Set for audio mixing. It is not recommended to intermix commands from the two command sets.

The Basic Command Set treats the CAT 860 as a simple audio switcher where only one of four audio/video sources is enabled at one time. The two microphone channels are controlled as a pair independently from the audio/ video sources. The low-cost serial controllers with their limited functionality will typically will be restricted to a subset of the Basic Command Set. These controllers usually cannot utilize the query commands, or the response packets. More capable high-end serial controllers can take advantage of the complete features of the Basic Command Set.

The Advanced Command Set treats the CAT 860 as an audio mixer which is aligned with the traditional usage for Lightspeed CAT 800 series products. The Advanced Command Set requires the more capable high-end serial controllers to utilize the CAT 860 to its greatest potential.

It is expected that each button press from the serial controller would use only a single action/query command packet. If a single button press must issue a string of multiple action/query command packets then each packet must be separated by at least a 10ms delay, or alternately, a new command packet must wait until the CAT 860 issues a response packet/character before it can be sent.

5. Warranty, Safety	& Specifications
4. Troubleshooting
3. Optional	Accessories
2. Setup & Use
1. Overview

30 31