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| Section 12
12.2 Serial Data
In addition to GPIO data, the Z/IP ONE can send low-bitrate serial data. Where GPIO is a series of discrete signals,
serial data is sent as a constant stream. The Z/IP ONE can transfer serial data at a sustained rate of 9600 bits per
second, and can send binary data as well as text.
To send serial data, the Z/IP ONE needs a USB-to-RS-232 adapter. This is available from Telos as an accessory, part
number 2091-00140. As of this writing, we specify a Syba SY-ADA15006. You may try any adapter that uses the
PL-2303 chipset, common among USB-to-serial adapters.
Since the Z/IP ONE is a USB host device, it acts as Data Terminal Equipment (DTE). Serial devices which
communicate as Data Circuit-terminating Equipment (DCE) may connect to the 9-pin connector directly. To use
the Z/IP ONE with another DTE device (such as a computer or laptop), a null modem will be required. The serial
port on the communicating device should be set to 9600 bits per second, 8 data bits, no parity, and one stop bit
(9600 8N1).
Plug the USB-to-serial adapter into either of the Z/IP ONE’s USB ports. In a moment, a message will appear on the
display informing you that the adapter is ready to use. When the adapters are installed in both Z/IP ONEs, make
a bidirectional connection between them. When the decoders lock, any serial data entered into one device will be
sent to the other, and out its serial port.
The serial data is correlated to the audio, with a small offset in time. Bidirectional communication is possible, but
any equipment using this for unattended communication must be able to tolerate the end-to-end delay in com-
munications. Also, just as audio data may be lost in transit, so may serial data. We compensate for this in the audio
codecs by using error concealment to hide the loss. Any serial communications equipment must likewise be able to
compensate for lost data.
