Symbol Technologies MK1000 - Manual (Page 108)

5-6
MK1000 MicroKiosk Product Reference Guide
Example 5 - MK1000 Waiting for Serial Response Time-out Period
PCK RS-485 Communication Protocol
When communicating via RS-485, the host computer must poll each MK1000 individually.
Therefore, each MK1000 has a unique address programmable by bar code menus. The
value of the address ranges from hex 30 (48 decimal) to hex 4F (79 decimal).
The poll command format is:
<EOT> <ADDR> <ENQ>
The host and the MK1000 communicate with each other using the following packet format:
<SOH> <ADDR> <STX> <DATA> <ETX> <LRC>
If the MK1000 is polled and has no data, it responds with an EOT character.
The same ACK/NAK protocol used for RS-232 is used for RS-485 communication.
MK1000 Host
<STX> <DATA> <ETX> <LRC>
<ACK>
<EOT>