Recently, several new packeteers using PK-232s have appeared on our local duplex repeater which is dedicated to packet radio. This is one environment where the collision frequency should be very low since there are no hidden terminals. Almost immediately we noticed that the collision frequency had risen dramatically. After some investigation we discovered certain stations were almost guaranteed to be involved in stepping on in-progress packets. These stations were contacted and in all but 1 case they were new users of PK-232s. We were very puzzled as there have always been some stations on the repeater using PK-232s with no apparent problems. The new stations were asked how their station was configured and what method was used to get the DCD operation adjusted. We were very surprised at the answers we got. Every single one of the offending stations had set their station up exactly according to the instructions in the PK-232 manual. However, contrary to the advice given in the manual, none of these stations had configured their setup so that they could hear what was going on on the channel when the PK-232 was connected to the radio. None of these new operators knew what DCD meant, what it did, or why it was important that it should be working on a multiple access packet channel. We obtained a PK-232 and manual to try and discover the exact nature of the problem. What we found was that although the manual is very complete and generally very well written, there are some areas where it leaves something to be desired. Specifically, in this case, the instructions given on page 2-16 (we had manual PK232UG Rev. B 9/86 for reference) for setting up the PK-232 and an FM radio for DCD operation are simply incorrect. If set up exactly as described, DCD will NEVER be asserted during a packet transmission by another station on the channel!! We had found the cause of our problem. If you have a PK-232 and haven't already discovered this problem for yourself, please disregard the instructions in the manual for setting up a PK-232 and NBFM radio for 1200 baud packet operation and use the method presented here. All your packet neighbors will appreciate it very much. The manual is quite corect in all respects EXCEPT where they discuss setting the DCD THRESHOLD control and receiver audio output level for proper demodulation and DCD circuit operation. The correct way to set these adjustments is as follows: 1. At least temporarily, arrange to be able to hear the receiver audio signal which is being sent to the PK-232. 2. Set the squelch circuit on the radio for normal squelched operation. The DCD circuit in the PK-232 is incapable of proper operation with unsquelched audio from the receiver. 3. While monitoring incoming packets, adjust the receiver audio level so that the tuning indicator "spreads" fully when receiving a packet from the station on the channel which produces the LEAST amount of audio output level. There are several limiters in the PK-232 demodulator so louder stations will not be affected adversely by this. 4. Once the audio level is properly set, adjust the DCD THRESHOLD control on the PK-232 so that the DCD led lights when there is a packet being transmitted by the station on channel which produces the LEAST amount of audio output from the receiver. Make sure, however, that the DCD LED is extinguished when there is no signal and the radio's squelch circuit has cut off all audio from the receiver. If the above procedure is followed, the PK-232 will properly hold off transmitting during a packet transmission from another station and will not send acknowledgements to individual frames of a maxframe greater than 1 packet while it is still being transmitted. We hope PK-232 owners will find this information useful and take steps to assure that their DCD is operating properly. Multiple access packet channel throughput is severely degraded when DCD is not working. 73 and happy packeting, Eric Gustafson N7CL