1.) Yes, you can send them that letter; there is no time limit to invoke the "inconvenience clause". Just tell them "all phone calls are inconvenient, any time and any place".
IMHO, that means voice-based phone service in ANY form, whether voice mail, VoIP, wireless phone, or vanilla "Ma Bell" service.
2.) Frankly, the additional restriction "contact by postal mail only" is obsolete since e-mail is, in fact, written communication, the Internet version of the letter in the mailbox.
So are chat rooms and other social networking programs (including a board like this one) as proxy for newspapers, typewritten discourse, and bulletin boards).
Ditto for text messaging.
Therefore all of these conceivably could be permitted was for the debt collector to communicate with the consumer debtor when the "inconvenience clause" is invoked.
However, under further analysis, the chat room/social networking media are written but would violate any or all of the following FDCPA clauses: §804(4) [communication by post card prohibited]; §805(b) [communication with third parties prohibited];§806 in general [harassment or abuse prohibited];§808 in general [unfair practices prohibited].
3.) The new electronic "TTD/TTY"--IP Relay--uses the Internet and VoIP protocol and comes out, of course, as text. This page from the FCC website explains further:http://www.fcc.gov/cgb/consumerfacts/iprelay.html
IP Relay allows people who have difficulty hearing or speaking to communicate through the telephone system with hearing persons. IP Relay is accessed using a computer and the Internet.... So individuals who use IP Relay do not need to invest in a TTY; they simply use the computer to communicate by text....
Unlike traditional TRS,...the first leg of an IP Relay call goes from the caller’s computer, or other Web-enabled device, to the IP Relay Center via the Internet. The IP Relay Center is usually accessed via a Web page. The second leg of the call, as with traditional TRS, is from the CA to the receiving party via voice telephone through the public switched telephone network.
There are no additional costs to consumers for IP Relay beyond a computer or other Web-capable device and an Internet connection.
IP Relay, as traditional TTY service, is really a hybrid of text and voice messaging that does, at some point, travel over phone lines. Whether the use of IP Relay to communicate between a debt collector and a debtor with a hearing or speech impairment constitutes written or phone communication as defined or implied in the FDCPA and case law may be legally yet unsettled.
IMHO, I'd treat it as voice and hence covered by the "inconvenience clause", but I need to research this question further.
I don't know how TTD/TTY is classified for FDCPA purposes. There may well be case law on this one that treats it as voice. As a reasonable substitute for audio phone service for those who need it, I would say the inconvenience clause applies although the result is text.
Again, more research is needed to confirm if this is indeed the case.