The Comet Serial is a Caller ID unit with RS232 serial connectivity. 
 
It is a Caller ID device for decoding the Caller's telephone number from the telephone line and presenting it on a COM Port of a PC. This product is powered entirely from the serial port. This is a hardware only product and can be used with your existing software to create a fully integrated call management solution.
 
CTI Comet Serial - User and Development Guide
 
The Comet Serial is a simple Caller ID product. It does not have Dialled Digit Detection, On Hook/Off Hook monitoring or Call Recording features.
 
Applications
 
The CTI Comet Serial has many applications. Below are some examples:
EPOS terminals in fast food outlets
Customer verification for taxi companies
Doctors and Dental surgeries
Incoming call Logging
 
Volume Pricing
Quantity discounts are available for volume purchases as follows:
2 off - £123 per unit
5 off - £110 per unit
10 off - £97 per unit
20 off - £87 per unit

We have introduced 2 specification options for the Comet Serial in terms of the cables which are provided with them:

The standard Comet pack includes the RS232/Serial cable and an RJ10 to BT Plug cable for use with standard UK telephone lines.

The new 'VoIP/International' variant contains the USB cable, and the UK/BT telephone cable is replaced with an RJ10 to RJ11 cable for use outside the UK and with Analogue Telephone Adaptors for VoIP lines.