When determining the number of recording channels needed one of the things you will want to think about is do you want to record A) phones or, B) phone lines.  Depending on what kind of organization you have you might have more phones than phone lines or vice versa.  You would want to take this into consideration because if you have less phones than phone lines then obviously if you recorded the phones, you would need less recording channels and therefore your system would be less costly.  When selecting a recording system, quite possibly the biggest price tag will be the cost per recording channel.

You might also have radios that you would like recorded.  If you do then one of the things you will want to check is: does each radio you want recorded have a mixed output jack.  In some cases we have encountered radios that have separate output jacks for send and receive.  This would require some kind of external mixer or two recorder channels per radio.

This question is usually pretty simple: Digital or Analog.  Again another consideration that needs to be observed is if you are recording Phones or Phone Lines.  If you are a small organization and are getting your phone lines from the local phone company then the phone lines are most likely Analog.  If you are a large organization with 50+ phone lines then you likely have a T1 which is Digital.  If it is phones that you want to record then one tell-tale sign of Digital verses Analog phone is: pick up your phone and dial your home phone number, when you press the digits on the dial pad, do you hear the same tone for each digit or are they different for each digit pressed?  If they are all the same tone, then your Phone is Digital.  If each tone is different then your phone is most likely Analog (there are exceptions however).  Whoever maintains your phones and phone lines should be able to answer the Digital or Analog question for you.

This is the amount of time that, on average, each phone is in use per call.  For example: if you were a telemarketer, your average call length would only be a couple of minutes because people tend to hang up on you.  This is used to calculate the amount of storage you need.

This is the amount of time, on average, each phone is not in use between calls.  This is used to calculate the amount of storage you need.