RS232 speed comparison under UZIX


     To know how some of the many RS232 interfaces available for MSX behave under the UZIX operating system, a simple test was made with them the compare the resulting reception/transmition times.
     The test itself is very simple: it consists in, giving a RS232 interface and a speed, connecting the MSX into a Linux box using the PPP and TCP/IP protocols. Once connected, the connection speed is tested measuring the time spent to send and receive a data packet. 20 packets are sent (and, hopefully, received) from MSX to the Linux box and the roundtrip time is measured, giving us an average value of the speed of the link. The reverse case is also tested (20 packets are sent from the Linux box to MSX and the roudtrip time is measured). Previous tests show that 20 packets is a sufficient number for our tests, and incresing it will not make our results more accurate. Each packet sent/received has a total of 64 bytes, including data and packet headers.
     For practical purposes, the well-known ping application was used for sending/receiving data. Thus, some facts are assumed: Some conclusions: Legend:
MSX Turbo-R, R800 mode
Sender: MSX    Receiver: Linux box
 
Speed (bps) Serial Interface
MSX-Serial 232 (ASCII) SVI-737 (Spectravideo) CT-80NET (Gradiente) RS232C (Sunrise)
(DMA on) (DMA off)
1200 NT NT NT NT NT
2400 NT NT NT NT NT
4800 NT NT NT NT NT
9600 221/231/255 229/295/337 230/259/323 221/282/323 204/274/289
19200 102/159/221 X --/--/-- --/--/-- 102/123/221
38400 102/159/306
57600 102/138/221



MSX Turbo-R, R800 mode
Sender: Linux box    Receiver: MSX
 
Speed (bps) Serial Interface
MSX-Serial 232 (ASCII) SVI-737 (Spectravideo) CT-80NET (Gradiente) RS232C (Sunrise)
(DMA on) (DMA off)
1200 NT NT NT NT NT
2400 NT NT NT NT NT
4800 NT NT NT NT NT
9600 370/429/475 402/483/513 399/489/550 390/501/617 370/428/450
19200 290/362/399 X X X 270/321/370
38400 230/299/313
57600 230/288/290



MSX2+, Z80 at 7MHz
Sender: MSX    Receiver: Linux box
 
Speed (bps) Serial Interface
MSX-Serial 232 (ASCII) SVI-737 (Spectravideo) CT-80NET (Gradiente) RS232C (Sunrise)
(DMA on) (DMA off)
1200 NT NT NT NT NT
2400 NT NT NT NT NT
4800 NT NT NT NT NT
9600 374/439/476 X --/--/-- 392/412/510 391/427/442
19200 289/381/476 X X X 340/362/374
38400 306/332/357
57600 ---/---/---



MSX2+, Z80 at 7MHz
Sender: Linux box    Receiver: MSX
 
Speed (bps) Serial Interface
MSX-Serial 232 (ASCII) SVI-737 (Spectravideo) CT-80NET (Gradiente) RS232C (Sunrise)
(DMA on) (DMA off)
1200 NT NT NT NT NT
2400 NT NT NT NT NT
4800 NT NT NT NT NT
9600 550/592/630 X --/--/-- 608/610/610 520/534/610
19200 470/523/590 X X X 470/483/490
38400 420/434/450
57600 ---/---/---



MSX Turbo-R, Z80 mode
Sender: MSX    Receiver: Linux box
 
Speed (bps) Serial Interface
MSX-Serial 232 (ASCII) SVI-737 (Spectravideo) CT-80NET (Gradiente) RS232C (Sunrise)
(DMA on) (DMA off)
1200 NT NT 2142/2625/3236 NT NT
2400 NT NT --/--/-- 1377/1625/1751 NT
4800 NT NT --/--/-- --/--/-- NT
9600 1190/1311/1479 X --/--/-- --/--/-- 816/827/850
19200 799/1228/1275 X X --/--/-- 680/782/833
38400 611/780/903
57600 --/--/--



MSX Turbo-R, Z80 mode
Sender: Linux box    Receiver: MSX
 
Speed (bps) Serial Interface
MSX-Serial 232 (ASCII) SVI-737 (Spectravideo) CT-80NET (Gradiente) RS232C (Sunrise)
(DMA on) (DMA off)
1200 NT NT 3603/3950/4627 NT NT
2400 NT NT --/--/-- 1856/2100/2360 NT
4800 NT NT --/--/-- --/--/-- NT
9600 1080/1169/1300 X --/--/-- --/--/-- 950/972/999
19200 910/983/1070 X X --/--/-- 830/878/900
38400 787/840/995
57600 --/--/--



MSX 2+, Z80 at 3.5MHz
Sender: MSX    Receiver: Linux box
 
Speed (bps) Serial Interface
MSX-Serial 232 (ASCII) SVI-737 (Spectravideo) CT-80NET (Gradiente) RS232C (Sunrise)
(DMA on) (DMA off)
1200 NT NT NT NT NT
2400 NT NT NT NT NT
4800 NT NT NT NT NT
9600 1292/1320/1360 X --/--/-- --/--/-- 1173/1214/1309
19200 1241/1294/1326 X X X 765/783/833
38400 782/798/799
57600 --/--/--



MSX 2+, Z80 at 3.5MHz
Sender: Linux box    Receiver: MSX
 
Speed (bps) Serial Interface
MSX-Serial 232 (ASCII) SVI-737 (Spectravideo) CT-80NET (Gradiente) RS232C (Sunrise)
(DMA on) (DMA off)
1200 NT NT NT NT NT
2400 NT NT NT NT NT
4800 NT NT NT NT NT
9600 1127/1217/1330 X --/--/-- --/--/-- 940/984/1016
19200 990/1042/1110 X X X 820/882/930
38400 820/860/900
57600 --/--/--