Hmmm.
Okay, to clarify, I send this to the device:
GET /tvnb?sessionid=0000001400c2002900&op=channellist&withrating=1 HTTP/1.1
This is actually Frame 73 of the exchange.
The device then sends back Frame 74 which is 66 bytes, followed by Frame 75 which contains 85 bytes of data (which I can access using Telnet.GetMessage(s)

:
HTTP/1.1 200 OK
Content-Type: text/plain
Content-Length: 892
X-1seg-Result: 14
Frame 76 (66 bytes) is then sent to the device, followed by Frame 77, also 66 bytes.
The device then responds with Frame 78 Frame 79, Frame 80, Frame 81, Frame 82 and Frame 83 (each containing 74 bytes), before it finally sends Frame 84 which containst the data I'm interested in, namely 892 bytes of data:
1_1_cbms://thomson.net/service/105|00|3|1|||0|1|en|Sony Max
1_1_cbms://thomson.net/service/111|00|3|1|||0|1|en|E! Entertainment Mobile
1_1_cbms://thomson.net/service/108|00|3|1|||16|1|en|Africa Magic
1_1_cbms://thomson.net/service/109|00|3|1|||0|1|en|Channel O
1_1_cbms://thomson.net/service/107|00|3|1|||0|1|en|TRACE Urban
1_1_cbms://thomson.net/service/104|00|3|1|||0|1|en|SuperSport Blitz
1_1_cbms://thomson.net/service/101|00|3|1|||0|1|en|SuperSport 1
1_1_cbms://thomson.net/service/103|00|3|1|||0|1|en|SuperSport 2
1_1_cbms://thomson.net/service/102|00|3|1|||0|1|en|SuperSport 3
1_1_cbms://thomson.net/service/113|00|3|1|||0|1|en|SuperSport 4
1_1_cbms://thomson.net/service/110|00|3|1|||0|1|en|eNews
1_1_cbms://thomson.net/service/112|00|3|1|||0|1|en|CNN
1_1_cbms://thomson.net/service/106|00|3|1|||0|1|en|Cartoon Network
1_1_cbms://thomson.net/service/115|00|3|1|||18|1|en|M-Net Series
I want to know how I can access this data. Telnet.GetMessage(s) does not give it to me.
I though that it may be an issue with the string, 's' containing a null value which would truncate it, but the actual data doesn't contain any such null character. If I can access Frame 75 using GetMessage, why can I not access Frame 84?