Emm-labs PRE2-SE User Manual download pdf (Page 20)

020

Appendix A - PRE2 Serial Remote Control (RS232)

PRE2 STEREO PREAMPLIFIER OWNER’S MANUAL

PRE2 Serial Remote Control (RS232)

Remote Control Protocol

e PRE2 Remote Control protocol is dened with the goal of structural simplicity and ease of implementation. Typical

implementation requires only a standard, asynchronous UART/RS232 port. At the Data Link level the following assumptions

are made:

• Short, xed-length data frames

• Data encoding uses only ascii (printable) characters

• Data frame has a checksum eld for error detection, but the checksum opt-out is possible at sender’s request - in such a

case, Sender’s frame has a standard blank checksum, and the Receiver side does not check against it.

At the Application level (i.e. remote control of a product) the message processing will be stateless:

• Each message is handled independently

• Each command acted upon immediately.

Frame Structure

e PRE2 frame structure is shown in the following diagram:

Frame preamble : < > Asterisk character.

Destination Product Class : P1, P0 two alphanumeric characters (a preamplier product will be denoted as "PR").

Command Message : M3, M2, M1, M0 typically 4 characters long, but it is product-dependent.

| Product Class

P1 P0 M3 M2 M1

C1 C0

| Command Message

| Cheksum |

1 2 ... 15 16 17 18 19 20 21 22 23 24 25

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Emm-labs PRE2-SE User Manual Page 20