Tom, You can find a schematic for the IP-2718 at: http://www.circuitarchive.co.uk/heath.htm Regards, Gary. Listserver Subscription:listserv at listserv.tempe.gov - "subscribe heath 'name' 'call'" Listserver Submissions: heath at listserv.tempe.gov Listserver Unsubscribe: listserv at listserv.tempe.gov - -"signoff heath"