The rate at which commands can be sent to a pan/tilt unit (PTU) depends on the PTU series and the connection speed. The E-series supports 100+ commands/second in both ASCII and binary form. The D-series is limited to 10 commands/sec for ASCII and 30 commands/sec for binary.
Command synchrony must be maintained since there is no hardware flow control. This means that the response from a prior command must be received before sending a new command. Commands should not be sent without keeping track of responses.