I am having trouble sending ZPL label data using "Write Value without Response" to characteristic 38EB4A82-C570-11E3-9507-0002A5D5C51B over BLE on a ZebraZD410 printer. I am using iOS's CoreBluetooth framework to communicate with the printer.
According to Zebra's documentation here: https://www.zebra.com/content/dam/zebra/software/en/application-notes/Ap..., the BLE characteristic 38EB4A82-C570-11E3-9507-0002A5D5C51B supports "Write Value with Response" and "Write Value without Response"
My iOS application can send data using "Write Value with Response" without a problem, but using a "reliable" transfer method results in **very** slow print speeds.
If I instruct iOS to send data using "Write Value without Response", I get a warning with the following message:
CBCharacteristic: 0x282668b40, UUID = 38EB4A82-C570-11E3-9507-0002A5D5C51B, properties = 0x8, value = (null), notifying = NO> does not specify the "Write Without Response" property - ignoring response-less write
This warning leads me to believe that the ZebraZD410 printer is incorrectly broadcasting the supported write capabilities during characteristic discovery, and iOS prohibits transferring data using an "unsupported" method.
Is there any guidance?