Here's the revised list of popular receivers with their appropriate firmware cable split into two sections for the ease of use. Feel free to add more receivers to this list.
NULL MODEM CABLE
* Ariza Ultra 400/500- Null modem cable
* Blackbird and all Blackbird clones(BOB, Max 1000, Stealth II. MS1000, ,etc.)- Null cable
* Buzz S2010F - Null modem cable
* Co0lsat 4000 Plus-Null modem cable
* Coship (All)-Null modem cable
* Digiwave 6800/7000-Null modem cable
* Dreambox (All)-Null modem cable
* Lava 2600-Null null modem cable
* Max 2500-Null modem cable
* Microroyal (All)-Null modem cable
* Orasat v5- null modem cable
* Pansat 2700-Null modem cable
* Pansat 3500-Null modem cable
* Pansat 5000HC-Null modem cable(Also can program through USB)
* Pantec/Multistar Max (All)=Null modem cable
* Rex1-Null modem cable
* Silver bullet/ST 1000/2000-Null modem cable
* Spacestar DVB500-null modem cable
* Stealth 2000a-Null modem cable
* Ultrastar 5000-Null modem cable
* Viewsat VS2000-Null modem cable
* Buzz S2010F - Null modem cable
STRAIGHT THROUGH CABLE
* Astrovox 2600-Straight through DB9
* Co0lsat 4000 Pro/5000-Straight through DB9
* Cooltec-Sraight through DB9
* Digiwave Diamond-Straight DB9
* Fortec lifetime-Straight through DB9
* Fortec Lifetime Ultra-Straight through DB9
* lava 3200- straight through db9
* Megasat (All)-Straight through DB9
* Pansat 2300a/2500a and all clones-Straight through DB9
* Pantec/Multistar MS (All except MS1000)-Straight through DB9